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Arcturus Publishing Limited
26/27 Bickels Yard
151–153 Bermondsey Street
London SE1 3HA
Published in association with
foulsham
W. Foulsham & Co. Ltd,
The Publishing House, Bennetts Close, Cippenham,
Slough, Berkshire SL1 5AP, England
ISBN: 978-0-572-03335-4
This edition printed in 2007
Copyright © 2007 Arcturus Publishing Limited
All rights reserved
The Copyright Act prohibits (subject to certain very limited exceptions)
the making of copies of any copyright work or of a substantial part of
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process. Written permission to make a copy or copies must therefore
normally be obtained from the publisher in advance. It is advisable also
to consult the publisher if in any doubt as to the legality of any copying
which is to be undertaken.
British Library Cataloguing-in-Publication Data: a catalogue
record for this book is available from the British Library
Printed in China
Created by: Q2A Media
Editors: Ella Fern and Fiona Tulloch
Cover design: Q2A Media/Steve Flight
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Contents
Universe
Galaxies
Stars
The Sun
The Planets
The Hot Planet
The Earth’s Twin
The Red Planet
The King of Planets
The Last Planets
Dwarf Planets
The Moon
Comets and Asteroids
Humans in Space
Planet Earth
Earth’s Atmosphere
Seasons and Climate
Mountains, Valleys and Caves
Other Landforms
Oceans
Volcanoes
Earthquakes and Tsunamis
Hurricanes and Tornadoes
The Living Planet
Monkeys
Apes
Big cats
Bears
Canines
Elephants
6-25
6
8
10
12
14
15
16
17
18
19
20
22
24
26-41
26
28
30
32
34
36
38
40
42-101
42
44
46
48
50
52
Hoofed Animals
Odd-toed Mammals
Odd Mammals
Whales
Other Marine Mammals
Seabirds
Birds of Prey
Songbirds
Waterfowl
Flightless Birds
Penguins
Fish
Friends and Enemies at Sea
Sharks and Rays
Life of a Fish
Reptiles
Lizards
Turtles
Snakes
Venomous Snakes
Constrictors
Crocodilians
Amphibians
Insects
Insect Life
Origin of Life
Dinosaurs
Armoured Dinosaurs
Plant-eating Dinosaurs
Meat-eating Dinosaurs
Other Prehistoric Animals
Plant Life
Food for Plants
Trees and Shrubs
Aquatic Plants
Climbers and Creepers
Human Body
External Body Parts
Bones and Muscles
Digestion and Excretion
The Heart and Circulation
The Brain and the Senses
Reproduction and Birth
Falling Sick
53
54
55
56
58
60
61
62
63
64
65
66
67
68
70
72
73
74
75
76
78
80
82
84
86
88
90
91
92
93
94
96
98
99
100
101
102-109
102
103
104
106
107
108
109
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Continents, Countries and People 110-123
North America
South America
Australia and Oceania
Europe
Africa
Asia
The Poles – The Arctic and Antarctica
World History
Ancient Mesopotamia
Ancient Egypt
Ancient India and China
Ancient Greece
Ancient Rome
Ancient Americas
Native Americans
Medieval Europe
Medieval China and Japan
Mughal India
Incas and Aztecs
The Renaissance
Discovery of New Lands
The British Empire
The Industrial Revolution
Scientific Revolution
The American Revolution & Civil War
The French Revolution
Napoleonic Wars
The World Wars
The World after World War II
Computer Revolution
The New Millennium – 21st Century
Art and Culture
Architecture
Art and Artists
Music
Theatre
World of Sports
World of Movies
World Religions
Science and Technology
Matter
Light
Sound
Heat
Electricity
Magnets
110
112
114
116
118
120
122
124-163
124
125
126
128
130
132
133
136
138
140
141
142
144
146
148
150
152
154
156
158
160
162
163
164-177
164
166
168
170
172
174
176
178-199
178
180
182
184
186
188
Forces and Motion
Communication and Satellites
Land Transport
Water Transport
Air Transport
190
192
194
196
198
World Map
200-201
Index
202-208
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Universe
Galaxies
The universe is a huge open space made up of billions of
galaxies and an even larger number of stars. Our galaxy is called
the Milky Way. Our solar system, including the Sun, the planets
and their moons, forms just a tiny part of the Milky Way.
Quick Q’s:
1. What is the Big
Bang theory?
The Big Bang theory
suggests that the
universe as we know
it today was created
after a huge explosion
or ‘bang’. Georges
Lemaitre proposed
the theory of the
Big Bang in 1927, and
in 1929 Edwin Hubble
expanded on his work.
2. Which is the
largest galaxy?
Scientists do not know
exactly. The largest
galaxies we know of are
giant elliptical (oval)
galaxies located in
the middle of a whole
group of galaxies.
One of the largest
is in the central
galaxy in the cluster
Abell 2029.
3. How big is the
Milky Way?
The Milky Way is huge.
It takes the Sun about
250 million years
to orbit once around
the centre of the
Milky Way.
4. What is Messier
Object 31?
The Andromeda
Galaxy is also known
as Messier Object 31,
or M31. This galaxy
is more than twice the
size of Milky Way. But
it is still not the largest
galaxy we know of.
6
Q How was the universe formed?
A The universe was born more than
15 billion years ago. It is believed that the
universe began as a small ball of fire. This
fireball grew larger and larger until one day it
exploded, to form the universe that we know.
Early universe
Scientists think that the early universe was a dense
cluster of matter, that has kept expanding from the
Big Bang until now and is continuing to expand.
Q How big is the universe?
A No one knows how big the universe
Q What is a galaxy?
A A galaxy is a group of billions of stars,
really is. There are at least 100 billion
galaxies that we know of. However, this
number keeps growing as better telescopes
are developed and we see more and more
galaxies. On top of that, the galaxies are
moving away from each other, causing the
universe to expand. Some scientists believe
that the universe will never stop expanding,
while others think that one day it will begin
to shrink until it becomes a fireball again.
dust and gas bound together by gravitational
force. A galaxy can either be on its own or in
a cluster. Galaxies come in different shapes
and sizes. Scientists have divided them into
three categories based on their shapes – spiral,
elliptical (oval) and irregular (no shape).
Expanding universe
Scientists think that stars and other elements in the
universe are continuing to move away from each other
due to the force of the original Big Bang.
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Galaxies
Q How did the Milky Way get its name?
A In ancient Greek and Roman myths, it was
believed that the goddess Hera (Juno) spilt
milk across the sky and called the white streak
it left a ‘river of milk’. The Romans called it
Via Lactea or a ‘road made of milk’. This is how
our galaxy came to be named the Milky Way.
A galactic crash
Sometimes, galaxies crash into one another due to the force of
gravity. But the stars in them are too far apart to cause any real
damage. Our own galaxy is on a collision course with its neighbour
Andromeda. The collision will take place in about five billion years
and the two will merge to form an elliptical (oval) galaxy.
Q Is the Milky Way a part of a cluster
of galaxies?
A The Milky Way and three of its
neighbouring galaxies are part of a larger
cluster known as the Local Group (because
they are closest to Earth). The neighbouring
galaxies in the Local Group are called
Andromeda, and the Large and
Small Magellanic Clouds. Of the
35 galaxies in the Local Group,
only these three can be seen
with the naked eye.
Milky Way
An artist’s impression of
our galaxy, the Milky Way,
based on observations
made by modern
telescopes. Our Sun is
a small star on one
arm of the galaxy.
Try these too…
Stars (8–9), The Sun
(10–11), The Planets
(12–13), Comets and
Asteroids (22–23),
Scientific Revolution
(150–151)
7
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Universe
Stars
A star is a huge ball of gas and dust that gives out both heat and
light. When the gases in the star burn out, it dies. A star can live
for millions, even billions, of years depending on its size. Each
galaxy in the universe is made up of several billion stars.
Quick Q’s:
1. How many stars are
there in the universe?
We know of about 70
sextillion (7 followed
by 22 zeros) stars in
the universe. However,
we are only able to see
about 8,000 of these.
2. What are giant and
dwarf stars?
Scientists classify stars as
giant or dwarf stars on
the basis of their size.
The Sun is a dwarf star.
Supergiant stars – the
biggest in the universe
– are at least 400 times
bigger than the Sun.
3. What is a cluster
of stars?
Stars are usually
found in groups called
clusters. Some clusters
are made up of loosely
packed stars, while
other stars are packed
tightly together to
form a dense cluster.
4. What kind of stars
are binary stars?
Pairs of stars are
called binary stars.
Binary stars revolve
around the same
centre of gravity.
5. Which is the
brightest known star?
The Pistol Star is the
brightest known star in
the universe. It is about
10 million times
brighter than the Sun.
8
Q What is a protostar?
A Stars are born in clouds of dust and
gases, mainly hydrogen. More and more gas
is pulled together by gravity to form a cloud.
After a while the cloud begins to spin. This
makes the gas atoms bump into each other at
high speeds, creating a great deal of heat. As
the cloud becomes hotter a nuclear reaction
takes place inside, and the cloud begins to
glow. This glowing cloud is called a protostar.
The protostar continues to contract until it
becomes a star.
Q How long does a star live?
A A star glows for millions of years until the
gases in its outer layer begin to cool, and the
hydrogen in the inner core is slowly used up.
The cool outer layer starts to glow red. When
this happens the star is called a red giant. The
red giant continues to lose its brightness until
it fades away. Depending on its size, a red
giant may die in an explosion, get compressed
to form a black hole or become a white dwarf.
Q What is a white dwarf?
A A small star usually shrinks to form a
dense white dwarf. The size of a white dwarf
is similar to the size of Earth. There are many
white dwarfs in our galaxy but they are too
dim to be seen. Sirius B is one of them.
White dwarf
An enhanced image of white dwarf stars, which have
already shrunk to a size comparable to that of the
Earth. These stars are too dim to be detected without
modern telescopes.
Protostar
An artist’s impression of the original ball of dust and
gases that combine to form a protostar.
Q What is a supernova?
A A supernova is a vast explosion in
which an entire star is destroyed. After the
explosion, extremely bright light is emitted
for several days. Supernovas appear a billion
times brighter than the Sun. Sometimes, a
supernova explosion can go on for weeks
or even months. Supernovas mostly occur in
distant galaxies. The last supernova to take
place in the Milky Way occurred in 1604. It
was observed by the famous astronomer
Johannes Kepler. The brightest supernova to
be recorded so far is 1993J in the galaxy M81.
It was seen on 26 March 1993. But because
the stars are so far away, we may see a
supernova explosion long after it takes place.
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Stars
Q What is a black hole?
A Black holes are extremely compact space
objects that were once massive stars. Sometimes
a huge star begins to shrink until it is smaller
than an atom. This is called a black hole. The
centre of the black hole is called ‘singularity’.
The gravity near this point is so strong that any
object that gets too close to the black hole is
pulled into it. Even light gets sucked into it,
which is why we can’t see a black hole. Scientists
use special instruments to detect a black hole’s
presence. They examine the effects it has on
the objects near it.
Dwarf stars
When stars reach the end
of their lives, their fires
start to die out, and then
they become dwarf stars
due to the gravitational
pull of the matter inside.
Black hole
Nobody can actually see
a black hole, because the
extremely strong gravity
inside them does not even
allow any light to escape,
let alone anything else.
This is an artist’s
impression of what a
black hole may be like.
Heavenly pictures
Try these too…
By drawing imaginary lines between the
stars in the sky, you will notice the shapes
of animals or objects familiar to you. You
might see a crab, a dragon, a bear or
other patterns. These star patterns are
called constellations. Astronomers have
identified 88 constellations in all. The
more famous ones are the Great Bear, the
Little Bear and Orion, also known as the
Hunter. The constellations also include
characters from Greek mythology and the
12 signs of the zodiac.
Galaxies (6–7), The Sun
(10–11), The Planets
(12–13), The Moon
(20–21), Humans in
Space (24–25), Earth’s
Atmosphere (26–27),
Scientific Revolution
(150–151), Computer
Revolution (162), Matter
(178–179), Light
(180–181), Heat
(184–185), Electricity
(186–187), Forces and
Motion (190–191),
Communication and
Satellites (192–193)
9
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Universe
The Sun
Our solar system is made up of the Sun, eight planets, three
dwarf planets and many asteroids, comets and other space rocks.
The Sun is the largest object in the solar system and is located
right at its centre. The planets, dwarf planets, asteroids and
comets travel around the Sun in an ellipse. Our solar system
was formed about 5 billion years ago, and the surface of the
Sun is about 4.6 billion years old.
Quick Q’s:
1. What are sunspots?
Sunspots are storms on
the surface of the Sun.
These storms appear
as huge, dark spots in
satellite pictures and so
are called sunspots.
2. How hot is the Sun?
The Sun’s surface
temperature is about
5,760 °C (10,400 °F),
while its centre is an
incredible 15 million °C
(28 million °F) –
that is more than
150,000 times hotter
than boiling water!
3. How far is the
Sun from us?
The Sun is about
150 million kilometres
(93 million miles)
away from the Earth.
4. What is the corona?
The corona is the
glowing atmosphere
of the Sun that extends
millions of kilometres
into space. The corona
is 200 times hotter
than the Sun’s surface!
5. Is the sun
worshipped by people?
The sun has been
worshipped as a god
since ancient times by
the Greeks, Romans
and native Americans.
10
Q How was the Sun created?
A Before it was formed, the Sun and the
rest of the solar system was a huge mass of
hot gas and dust called a solar nebula. This
nebula spun faster and faster until the clouds
of gases, dust and ice particles clumped
together and exploded, forming the sun.
Q Why does the Sun glow?
A The Sun is made up of huge amounts of
hydrogen and helium gases. Nuclear reactions
at the centre of the Sun emit a large amount
of energy that makes the Sun glow. That same
energy travels through space and reaches us
as heat and light.
Q What is a solar eclipse?
A A solar eclipse occurs when the Moon
comes between the Sun and the Earth,
blocking the Sun from our view. In a total
solar eclipse, the Moon blocks out the Sun
from our view completely. In a partial eclipse,
however, a part of the Sun is visible. During
an annular eclipse, we can see a small ring of
the Sun glowing around the Moon. When the
Moon is nearer to the Earth it appears larger
and therefore covers the Sun completely,
although it is actually much smaller than the
Sun. However, in an annular eclipse the
Moon is too far away from the Earth to block
the Sun out totally and therefore a ring of
sunlight is seen.
Flaring up!
Solar flares on the surface of the Sun. Solar flares were
observed for the first time in 1859.
Q What is a solar flare?
A Sometimes the Sun produces a huge
amount of magnetic energy that sends out
jets of gas into space. These jets of gas are
called solar flares and cause a sudden
increase in the brightness of the Sun. Solar
flares are often followed by the release of
electrically charged particles like protons
and electrons. These are called solar winds
and are known to travel at a speed of about
500 kilometres (300 miles) per second.
Blocking the Sun
In an annular (ring-shaped) eclipse, the Moon covers
only the middle portion of the Sun, causing a bright ring
of light to appear around the Moon.
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The Sun
Q Is the Sun really a star?
A The Sun is a medium-sized star known as
a yellow dwarf. It is younger and smaller than
most stars in the universe, but is very bright
and extremely hot. In about five billion years,
when all the hydrogen in its core has been
used up, the Sun will change into a red giant
star. After that, the Sun will evolve into a
white dwarf before finally dying out.
A joint effort
The SOHO was launched
jointly by the European
Space Agency and NASA.
For over ten years, SOHO
has been studying the
outer layers of the Sun.
Q How did we learn about the Sun?
A We have sent several solar missions
into space to study the Sun and its
characteristics. The first detailed
observations were made by
NASA’s Pioneer missions that
were launched between 1959
and 1968. The Solar Maximum
mission of 1980 made a detailed study of
solar flares. The Solar and Heliospheric
Observatory (SOHO) launched in 1995, has
been continuously collecting data regarding
the Sun for the last ten years.
In different directions!
The Sun takes about 26 days on average
to rotate on its axis. Since it is made up
of gas, different parts of the Sun rotate
at different speeds. The surface closest
to the equator rotates faster than that
closest to the polar regions. The Sun’s
surface near the poles takes almost 36
days to complete one rotation.
N
Try these too…
S
Surface of the Sun
There is constant activity
visible on the surface of
the Sun, as it pulses and
glows due to the heat and
light produced by the
nuclear reactions within.
Galaxies (6–7), The
Planets (12–13), The
Moon (20–21), Earth’s
Atmosphere (26–27),
Scientific Revolution
(150–151)
11
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Universe
The Planets
Planets are large masses of matter that orbit around
a star. Our solar system consists of eight planets –
Mercury, Venus, Earth, Mars, which are called inner or
rocky planets, and Jupiter, Saturn, Uranus and Neptune,
which are the outer planets, or gas giants.
Quick Q’s:
1. How did the planets
get their names?
All the planets are
named after Roman
gods. Venus is named
after the Roman
goddess of love. The
surface features of
Venus are also named
after various goddesses.
For example the planet
has a deep canyon
named Diana, after
the Roman goddess
of hunting.
2. How many rings
do Jupiter and
Uranus have?
Jupiter has three thin
rings that cannot be
seen even with the
most powerful
telescopes. Uranus
has as many as
11 rings.
3. How many moons
does Venus have?
Apart from Mercury,
Venus is the only other
planet in the solar
system that has no
moon.
Q How were the planets formed?
A After the gaseous cloud called the
solar nebula collapsed upon itself due to
the strength of its own gravity and formed
the Sun, the dust and particles around it
clumped together to form the planets.
The heat of the Sun melted the ice particles
nearby and eventually these rocks grew larger
to form the four rocky planets. Some ice
particles were too far away from the Sun to be
melted. These ice pieces combined with gases
to form the planets called the gas giants.
Birth of planets
The planets in our solar system were born when dust
and particles around the Sun clumped together.
Earth
Uranus
Jupiter
Neptune
Saturn
Gas giants
The four outer planets, the gas giants, are much larger
than the Earth.
Q What are the features of a rocky planet? Q What makes gas giants unique?
A The rocky planets are made up of rocks A The gas giants are bigger in size but
and metals like iron and nickel. They are
smaller than the gas giants but are very heavy.
It is because of their weight that rocky planets
rotate much slower than the gas giants.
Rocky planets
Among the rocky planets, the Earth appears blue from
outer space because over 70 per cent of its surface is
covered with water.
lighter, as they are mainly made up of gases
and ice particles. In fact, Saturn is so light
that it would float if placed in water! Gas
giants also spin extremely quickly and they
have rings around them. These planets do
not have a hard surface. Jupiter and Saturn
have a semi-liquid centre that is covered by a
layer of liquid gas.
4. What about Pluto?
Until recently, Pluto
was the ninth planet
in our solar system.
But in 2006, it was
officially reclassified as
a dwarf planet, because
it is so small and its
gravitational field is
not as strong as that of
the major planets.
12
Mercury
Mars
Venus
Earth
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The Planets
Try these too…
Q What are the distinguishing features
Galaxies (6–7), The Sun
(10–11), The Hot Planet
(14), The Earth’s Twin
(15), The Red Planet
(16), The King of
Planets (17), The Last
Planets (18), Dwarf
Planets (19), The Moon
(20–21), Earth’s
Atmosphere (26–27)
1
of each of the rocky planets?
2
A Mercury is the closest to the Sun and
JUPITER
therefore its temperature can be as high as
467 °C (873 °F). Venus is covered with carbon
dioxide containing droplets of sulphuric acid.
This traps the Sun’s heat and makes Venus
hotter than even Mercury. Mars, the red
planet, is considered to be the only planet
after Earth where life could exist. As far as
we know, the Earth is the only planet that
supports life.
Q What are the special characteristics
of the gas giants?
A Jupiter is the largest planet. It rotates
faster than any other planet and has the most
moons. Saturn is set apart by its beautiful
rings, made up of dust particles and pieces of
ice. Uranus is a strange planet where seasons
last for more than 20 years, while Neptune
is the windiest planet in the solar system.
3
1
2
3
4
Amalthea
Adrastea
Metis
Thebe
4
Jupiter’s moons
Jupiter, the largest planet
in the solar system, has so
many moons that we are
constantly discovering
new ones. This image
shows some of the bigger
moons and the gossamer
rings around the planet.
Saturn’s moons
At least 46 moons orbit Saturn. Each moon
is unique. Enceladus is among the shiniest
objects in space. Titan’s atmosphere is
thicker than Earth’s. Here are the big
moons, seen from behind the moon Dione.
The solar system
The relative sizes of the
eight planets and the
three dwarf planets are
shown in this diagram
of the solar system.
Jupiter is the largest
planet. The Sun, of
course, is much larger
than any of the planets.
Titan
Enceladus
Rhea
Saturn
Mimas
Tethys
Dione
PLANETS
1
3
4
5
6
7
1
2
3
4
5
6
7
8
8
2
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
DWARF PLANETS
9 Ceres
10 Pluto
11 2003 UB 313
9
10
11
13
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Universe
The Hot Planet
Mercury is the planet closest to the Sun. It is also very small –
about the size of Earth’s moon. It is named after the Roman
messenger god because it moves very quickly.
Quick Q’s:
Q Why are nights on Mercury freezing cold,
1. How long does
Mercury take to orbit
the Sun?
although it’s the planet closest to the Sun?
Like all planets,
Mercury goes around
the Sun in an elliptical
(oval) orbit. It takes
about 88 days to
complete one orbit.
2. How long is a day
on Mercury?
Mercury goes around
the Sun very fast, but
rotates very slowly on
its axis. Therefore a day
on Mercury is equal to
176 Earth days!
3. Why does Mercury
have huge craters?
As Mercury has very
little atmosphere,
meteors do not burn
up in the air. Instead,
they fall on the surface,
creating huge craters.
4. What colour is the
sky above Mercury?
A Unlike Earth, Mercury is not
surrounded by a thick protective blanket
of air called the atmosphere. This means
that the heat from the Sun escapes, leaving
the planet freezing at night. While the
temperature during the day can be as
high as 467 °C (873 °F), at night it drops
to -183 °C (-297 °F).
Q What is the surface of Mercury like?
A If you were to land on mercury, you
would find a surface very similar to that of
the Moon. It has dust-covered hills, cliffs and
is dotted by craters. The planet also has a
thick metallic core and
a sandy crust.
solar panel
Sun shade
Sandy surface
Mercury has a surface that is full of hills and steep
canyons, all of it covered with a mixture of sandy
substances. The core of the planet is metallic, like all
the rocky planets.
Q
What space probes have been launched
to Mercury?
A Mercury, being so close to the Sun, is
very difficult to explore. Space probes are
unable to withstand the heat of the planet.
Only one space probe, Mariner 10, has visited
Mercury so far. It photographed nearly half
of the planet’s surface. A new probe,
Messenger, is on its way to Mercury.
It was launched on 3 August 2004
and is expected to return, after
photographing the whole planet,
in March 2012. Another space mission
will begin in 2013.
TV cameras
If you were to look at
the sky from Mercury,
even during the day, it
would appear black.
This is because there is
no atmosphere to
spread the Sun’s light.
5. Which is the largest
crater on Mercury?
The largest crater is
the Caloris Basin. It is
about 1,300 kilometres
(808 miles) in
diameter. It is also one
of the biggest craters in
the solar system.
14
Mercury close-up
From up close, the surface of Mercury can be
seen to be pitted with huge craters.
Any meteor that comes near Mercury falls
on the surface and creates a crater, as there
is no atmosphere to burn the meteor up.
Looking at Mercury
The Mariner 10
space probe is the
only one to
have got
anywhere
near Mercury so
far. It is sending
photographs of the
surface of Mercury
regularly now.
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The Earth’s Twin
The Earth’s Twin
Venus is the second planet from the Sun. It is also Earth’s closest
neighbour and its size, composition, gravity and distance from
the Sun are similar to the Earth’s. Venus is so similar to Earth,
that it is often considered to be its twin. However, in reality,
Venus is very different.
Q Why is Venus hotter than Mercury?
A Venus has a thick atmosphere, much
thicker than the Earth’s. The atmosphere is
mainly carbon dioxide. This greenhouse gas
traps large amounts of heat within the planet.
That is why Venus is hotter than Mercury,
though Mercury is closer to the Sun.
Q Why is a day longer than a year
on Venus?
A Venus goes around the Sun at a very
high speed. It takes only about 225 days to
complete one orbit. However, it spins much
more slowly on its axis, taking about 243
days to complete a rotation. Therefore,
days on Venus are longer than years.
Mapping Venus
Scientists have sent
a number of space
missions to Venus to
find out more about
its size, atmosphere,
interior and surface,
especially its volcanoes.
Q Are there volcanoes on Venus?
A There are more volcanoes on Venus
than there are on Earth. About 80 per cent
of the planet’s surface is made up of smooth
volcanic plains, and there are two major
mountain ranges with volcanoes that may
be active. The peak of Maxwell Montes,
the highest mountain on Venus, lies 11
kilometres (7 miles) above the surface
of the planet. Mount Everest rises only
about 9 kilometres (6 miles) above sea level.
Try these too…
The Sun (10–11), The
King of Planets (17), The
Moon (20–21), Comets
and Asteroids (22–23),
Earth’s Atmosphere
(26–27), The Poles – The
Arctic and Antarctica
(122–123)
Volcano on Venus
There is far more volcanic
activity inside Venus than
inside Earth; so, Venus has
many more volcanoes.
Spinning backwards
All the planets rotate from west to east
on their axes, apart from Venus, which
spins in the opposite direction. On the
surface of Venus, the Sun appears to rise
in the west and set in the east. The planet
might have been hit by a huge space
rock, reversing the direction of its spin.
Earth
rotation
Sun
Venus
15
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Universe
The Red Planet
Mars is the fourth planet from the Sun and is named after the
Greek god of war. It is also called the red planet because it glows
red in the sky. The presence of rust (iron oxide)
on its surface gives the planet its colour.
Quick Q’s:
Q What is the
1. Can you see Mars
from the Earth?
surface of Mars like?
On a clear night, Mars
can be observed with
the naked eye. Between
July and September
the Martian surface
can be observed clearly
through a telescope.
2. How many moons
does Mars have?
Mars has two moons
called Phobos and
Deimos, which orbit
very closely to its
surface. Both moons
are believed to be
asteroids that were
captured by the
gravity of Mars as they
came close to it.
3. Is there life
on Mars?
The atmosphere
of Mars is 95 per cent
carbon dioxide, 3 per
cent nitrogen and
1.6 per cent argon.
Traces of oxygen
and water have also
been found. Some
scientists have claimed
to have found traces
of methane. This gave
rise to the speculation
that there may be
life on Mars, since
methane is a gas
produced by many
animals. But other
scientists pointed
out that methane is
also produced by
the mineral olivine,
which can be found
on Mars.
16
Martian moon
The two moons of Mars
are quite small compared
to our Moon. They may be
asteroids caught by the
gravity of Mars.
Red planet
The surface of Mars looks reddish brown
due to the presence of iron oxide.
The scientists have also found signs of
frozen water near the South Pole of
Mars. It is believed that huge floods
flowed through Mars about 3.5 billion
years ago. The water from the floods
may have once collected in huge basins.
A The surface of
Mars is divided into
the northern plains
flattened by lava flows, and
the southern highlands marked
by huge craters. The planet boasts Olympus
Mons, the largest volcano in the solar system.
Q Is there water on Mars?
A Scientists have found signs of water
in rock layers. In 2006, the scientists saw new
deposits of sediment on the surface of Mars.
These sediments had not been there six years
earlier. According to scientists at NASA, this
is the strongest evidence so far that water still
flows occasionally on the surface of Mars,
though other scientists say the sediments
could have been deposited by carbon dioxide
frost or movement of dust. Samples of the
minerals haematite and goethite have also
been found in Mars. These minerals are
sometimes formed in the presence of water.
Olympus Mons
The tallest volcano in the
solar system, Olympus
Mons towers 27 kilometres
(16.88 miles) above the
surface of Mars.
Q Why are seasons on Mars longer than on
Earth?
A
Mars and Earth are tilted on their axis in
the same way. Therefore, Mars has almost the
same kind of seasons as Earth. However,
because a Martian year is equal to two years
on Earth, each Martian season lasts twice as
long as the seasons on Earth.
Q
What kind of weather would you
find on Mars?
A The temperature varies from -140 to
20 °C (-220 to 68 °F). The polar ice caps on
Mars increase and decrease in size alternately
in winter and summer. Mars also has dust
storms, which can cover the entire planet.
Look out for Mars
From 27 August 2006,
Earth and Mars have been
closer to each other than
they have been in the last
60,000 years! It has begun
to appear brightly in the
night sky, as seen here
while looking south-east
from Poodle Rock in the
Valley of Fire State Park,
Nevada, USA. Now Mars
will be the brightest
object in the night sky
after the Moon and Venus.
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The King of Planets
The King of Planets
Jupiter is the first of the gas giants and the fifth planet from the
Sun. It is the largest of all planets. In fact, more than a thousand
Earths could fit inside it!
Q How did Jupiter get its name?
A The planet is named after the king of
the Roman gods. It is indeed the king of the
planets, not just because of its massive size,
but also because it rotates the fastest. It is the
fourth brightest object in the sky, after the
Sun, the Moon and Venus.
Q How many moons does Jupiter have?
A Jupiter has more than 60 moons. Galileo
Galilei, the famous Italian astronomer, saw
the four largest moons of Jupiter in 1610.
They were named Io, Europa, Callisto and
Ganymede. By the 1970s nine more moons
were discovered and today we know of 63.
Volcanic moon
Io, one of the four largest moons, lies
very close to Jupiter. There is a great deal
of pressure on this small moon, since it is
constantly being pulled by the gravity of
Jupiter and the other large moons. This
tug of war generates a lot of heat, so Io
is covered with active volcanoes.
Q
What is the
Great Red Spot?
Great Red Spot
A Jupiter is a
planet of storms. The
biggest storm area is
called the Great Red Spot.
It has been raging for at least
340 years. It is so big that
it can be seen from the
Earth through a telescope.
Q How many explorations have been made
to Jupiter?
A
Many explorations have been made to
the king of planets. Pioneer 11 took the first
close-up images in 1974, studied the
atmosphere and detected Jupiter’s magnetic
field. Space probe Galileo, launched in 1989,
orbited Jupiter. In 2000, the Cassini probe
took the best ever photos.
Planet spotter
The Galileo space probe was the first to make an entire
orbit around Jupiter.
Giant ball of gas
There are constant storms
on Jupiter, during which
the winds can roar five
times faster than the
fastest hurricane on Earth.
Some of the big storms are
seen here in brown.
Try these too…
The Sun (10–11),
The Planets (12–13),
The Last Planets (18),
The Moon (20–21),
Comets and Asteroids
(22–23), Scientific
Revolution (150–151),
Communication and
Satellites (192–193)
17
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Universe
The Last Planets
Next to Jupiter are Saturn, Uranus and finally Neptune. Saturn
is the second largest planet in the solar system. Like Jupiter,
Saturn and Uranus are made up of gases. All three planets have
rings, but it is Saturn’s rings that are the most spectacular.
Q Why do Saturn’s
rings shine?
A Saturn’s rings
consist of dust particles
and pieces of ice that
can be quite large. The
ice pieces reflect light,
causing the rings to shine.
Saturn’s rings
Saturn has seven large
rings, each made up of
thousands of smaller
rings. These are among the
brightest objects you can
see through a telescope.
Quick Q’s:
1. How big are Saturn’s
rings?
Q
What gives Uranus and Neptune
their blue colour?
A Both planets contain methane. Sunlight
is reflected by clouds under the methane
layer. Only the blue portion of the reflected
light passes through the methane layer, so
they appear to be blue.
Strange rotation
Uranus rotates from top to bottom as it orbits the Sun.
Saturn’s rings can
be up to 1 kilometre
(0.6 miles) thick
and stretch for over
280,000 kilometres
(175,000 miles).
2. When were Saturn’s
rings discovered?
4
Uranus was the first
planet to be seen
through a telescope.
It was discovered in
1781 by astronomer
William Herschel.
18
URANUS
3
1
1
2
3
4
5
over 20 years?
A
Uranus has a very peculiar orbit, unique
in the solar system. The planet is tilted in
such a way that its poles face the Sun directly,
so that Uranus spins from top to bottom. It
acts like a cylinder that is rotating on its ends
instead of rotating on its sides. Scientists
believe that another planet-like object might
have crashed into Uranus, knocking it over
on to its side. The long seasons are caused by
the planet’s unusual orbit.
Q Are there winds on Neptune?
A Neptune is the windiest planet in our
Cloudy over Neptune
The clouds over Neptune are always being blown about
by the strong winds on the planet.
2
3. Who discovered
Uranus?
Q Why do seasons on Uranus last for
solar system. Winds on this planet can
reach speeds of about 2,000 kilometres per
hour (1,200 miles per hour). That is more
than ten times the speed of the strongest
hurricane on Earth.
5
Saturn’s rings were first
observed by Galileo
through a telescope
in 1610.
Probing far
The Cassini space probe is expected to send us better
photographs of the far planets.
Pole
Equator
Juliet
Bianca
Puck
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Dwarf Planets
Dwarf Planets
In 2006, the International Astronomical Union (IAU) made a
decision that changed the way we organize our solar system. The
IAU announced the removal of Pluto from the list of planets.
They reclassified Pluto as a dwarf planet. Instead of nine, we
now have only eight planets in our solar system.
Q How is a dwarf planet different from
Q How many dwarf
other planets?
planets are there in
the solar system?
A According to the IAU’s new definition,
A Apart from
a planet is a space object that orbits the Sun
and has a nearly round shape. Its gravity must
be strong enough to clear all other space
objects (except satellites) out of its orbit.
Dwarf planets also orbit the Sun and have a
nearly round shape. But other space objects
nearby are not cleared by the gravity of the
dwarf planets. They are not big enough for
their gravitational fields to do this. Dwarf
planets are different from satellites, which
orbit a planet and not the Sun.
Pluto, Ceres and
Eris (UB313) have also been classified
as dwarf planets. Until recently, Ceres was
called the largest asteroid. It has a diameter
of about 950 kilometres (600 miles) and is
in the asteroid belt between Mars and
Jupiter. Eris is the largest of all the dwarf
planets. It has a diameter of about
3,000 kilometres (1,850 miles).
Q Are there any other dwarf planets?
A Scientists are considering including
Distant Sun
An artist’s impression of
how the Sun would look
from the surface of Eris,
the furthest of the dwarf
planets in the solar
system. The Sun gives
almost no heat at that
distance and looks like
a bright star.
Pluto’s moon Charon among the dwarf
planets. Charon does not actually go around
Pluto – they revolve around each other. The
planetoid Sedna and the asteroids Vesta,
Pallas and Hygiea are also being considered.
1
2
3
4
5
Sun
Mercury
Venus
Earth
Mars
6
7
8
9
10
Jupiter
Saturn
Uranus
Neptune
Pluto
Try these too…
The Sun (10–11), The
Planets (12–13), The
Red Planet (16), The
King of Planets (17),
The Last Planets (18),
The Moon (20–21),
Comets and Asteroids
(22–23), Scientific
Revolution (150–151),
The New Millennium –
21st Century (163)
Pluto’s moon
Pluto (left) and its moon Charon actually go around
each other, rather than Charon going around Pluto.
Scientists may soon reclassify Charon as dwarf planet.
Thrown off orbit
Pluto was called the ninth
planet for 76 years. After
2006, it was reclassified as
a dwarf planet.
Promoted
Since 2006, Ceres is
classified as a dwarf
planet. Before that, it was
simply the largest of the
many asteroids that lie
between the orbits of
Mars and Jupiter.
10
6
5
9
8
2
1
4
7
3
19
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Page 20
Universe
The Moon
There are many moons in our solar system, which orbit planets,
just like planets orbit the Sun. Earth has one Moon, Mars has
two small moons, Mercury and Venus don’t have any, while
Jupiter has at least 63! The Earth’s Moon is made up of rocks,
both solid and molten.
Quick Q’s:
1. Does our Moon have
a scientific name?
Astronomers call the
Earth’s Moon Luna,
to distinguish it from
the natural satellites
of other planets.
2. If the Moon is
cold and dark, how
does it give off light?
The Moon does not
give off light of its own.
It simply reflects the
sunlight that falls on it.
3. Why can’t we see the
Moon during the day?
During the day the
bright light of the Sun
blocks the soft glow
of light reflected by
the Moon.
4. What are spring
tides and neap tides?
When the Sun, the
Moon and the Earth
are in a straight line,
the gravitational force
of the Sun strengthens
that of the Moon
causing tides that are
higher than usual.
These are called spring
tides (although they
have nothing to do with
the season of Spring).
When the Sun and the
Moon are at right
angles to the Earth,
weaker tides, called
neap tides, are caused.
Tides are important to
wash away the debris off
the coasts.
20
Q
Why is the Moon’s surface filled
with craters?
A The Moon does not have an
atmosphere. Therefore, meteors and
asteroids from outer space crash into its
surface making craters. Tycho crater, one
of the biggest lunar craters, is more than
85 kilometres (50 miles) wide.
Q What does the term ‘Blue Moon’ mean?
Blue Moon refers to the second Full Moon
to appear in a month. It is very rare indeed.
There are other definitions of Blue Moon as
well, but this is the most widely accepted
definition nowadays.
Q
How does the Moon cause tides in
our oceans and seas?
A Tides are caused by the gravitational
force exerted by the Moon on our planet.
This force causes the ocean to bulge out in
the direction of the Moon, making the tide
rise. As the Earth is also pulled towards the
Moon, the ocean on the side facing away
from the Moon also bulges out. So it is high
tide there as well. In the region between the
two bulges (high tides) the water level
decreases, causing low tides. Tides are higher
in the tropics due to the bulge of the
equator. Many forms of life on the coast are
tailored to the cycle of tides.
High and low
The gravitational pull of the Moon on the Earth causes
tides in the oceans and seas of the Earth.
Crescent Moon
As the Moon orbits around the Earth, we see only a part
of it that is lit up by the Sun, depending upon the angle
made by the Earth, the Moon and the Sun.
Q
Why does the Moon appear crescentshaped at times?
A The shape of the Moon as seen from the
Earth keeps changing. The changing shapes
of the Moon are called phases. When the side
of the Moon that faces the Earth is turned
away from the Sun, we are unable to see the
Moon. This phase is called the New Moon.
As the Moon travels in its orbit around the
Earth, we start to see a small portion of the
Moon that is lit up by the Sun. This is called
the Crescent Moon. The lit up portion seen
by us slowly increases, and we see a Half
Moon, then a Three-quarter Moon. When
the Moon completes a half orbit around
the Earth, we can see the entire disc lit up
by the Sun – the Full Moon.
Neap
Tide
Spring
Tide
Sun
Low Tide
High
Tide
High
Tide
Low Tide
Neap
Tide
Spring
Tide
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The Moon
The dark side
Did you know that we see only one side of the Moon
at all times? This is because the Moon takes the
same amount of time to rotate on its axis as it takes
to go around the Earth. The side we see is called the
near side, while the one that is never seen is called
the dark side. The first time people on Earth got to
see the dark side of the Moon was when the first
astronauts made an orbit around the Moon, and
took photographs. The astronauts lost touch with
Earth when they were on the dark side, because the
moon blocked their radio signals.
Phases of the Moon
We see different parts of
the Moon lit up by the
Sun, depending upon how
much of the Moon that is
lit up is facing towards us
or facing away from us.
This is repeated in a cycle
every 28 days.
Try these too…
The Sun (10–11), The
Planets (12–13), Humans
in Space (24–25), Oceans
(34–35), Forces and
Motion (190–191)
21
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Universe
Comets and Asteroids
Along with the Sun, the planets and their moons, several other
objects made up of small pieces of rock, metal and ice are
also a part of the solar system. These objects are asteroids,
comets and meteors.
Mars
Mercury
Quick Q’s:
1. What are sungrazers?
Some comets crash
into the Sun or get
so close to it that they
break up into tiny
pieces. Such comets
are called sungrazers.
2. Where are asteroids
found in the solar
system?
Most asteroids are
found in a region
between Mars and
Jupiter, which is known
as the asteroid belt.
3. Do asteroids have
moons?
The asteroid Ida has
a tiny moon, Dactyl.
This was discovered
by the spacecraft
Galileo in 1993.
4. When will Halley’s
Comet be seen again?
Halley’s Comet takes
about 76 years to
complete one orbit
around the Sun, so
it is expected to be
seen again in 2061.
5. Why does a comet
have a tail?
A comet is made up
of ice and other
material. As it nears
the Sun, these materials
heat up. Solar wind and
pressure from the Sun’s
radiation push them
outwards to form a tail
that always points away
from the Sun.
22
Q Are asteroids planets?
A When the solar system was formed,
some fragments of rock were left spinning in
space. These huge space rocks that orbit the
Sun are called asteroids. Like other planets,
asteroids are also made of metals like iron
and have moons. Some of them are called
minor planets.
Q Are asteroids dangerous?
A An asteroid can be thrown off its orbit
by the gravity of larger planets, or if it comes
too close to another asteroid. Once it is off its
orbit, the stray asteroid often strikes the
surface of other planets and moons. This
causes widespread destruction and creates
huge craters. In fact, some scientists think
that an asteroid struck Earth about
65 million years ago, causing the extinction
of the dinosaurs.
Q Are shooting stars really stars?
A Shooting stars are actually pieces of
burning rock called meteors. A meteor is
formed when a piece of debris in the solar
system, called a meteoroid, enters the Earth’s
atmosphere. As the meteor rubs against the air
in the Earth’s atmosphere, it gets hotter and
hotter until it burns up in a streak of light.
A meteor
We can see a meteor without a telescope when it
enters the Earth’s atmosphere. Sometimes, a number of
meteors are seen within a very short period of time.
They leave a streak of light, which disappears very
quickly. This is called a ‘meteor shower’, also known
as ‘meteor storm’.
Venus
Earth
Jupiter
Asteroid belt
Most of the asteroids in our solar system can be found
in a belt between the orbits of Mars and Jupiter.
Q How is a comet’s tail formed?
A A comet is a mixture of ice, gas and
dust. Like asteroids, they too travel around
the Sun. As a comet nears the Sun, the ice
on its surface melts and a jet of gas and dust
particles is released to form a tail. Comet
tails can be as long as 10 million kilometres
(6.2 million miles).
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Comets and Asteroids
Q Do meteors ever fall on Earth?
A Sometimes small fragments of a meteor,
called meteorites, crash on to the surface
of the Earth. Some are so big that they make
craters where they fall. Many meteorites have
been found on the Earth’s surface. The best
known of these is the Barringer Impact
Crater in Arizona, USA. This crater was
created by an iron meteor that fell on the
Earth about 50,000 years ago. The meteor
was almost 40 metres (130 feet) in diameter
and slammed into the surface at a speed of
about 11 kilometres per second (6.8 miles
per second), creating a crater that was more
than a kilometre wide.
The great Siberian explosion
On 30 July 1908 people living near Lake Baikal in Siberia saw
a strange bluish light travel across the sky, followed by a loud
explosion and shockwaves that knocked people off their feet.
The explosion took place near the Stony Tunguska River and was
probably caused by a meteor. It flattened about 80 million trees.
The meteor may have broken up about 10 kilometres (6 miles)
above the Earth’s surface, so it did not leave a crater.
Huge crater
The Barringer impact
crater in the USA was
created by a meteorite
impact 50,000 years ago.
Q Where do comets come from?
A Comets originate in two different areas
of the solar system. Comets from the Kuiper
Belt beyond Neptune are called short-period,
since it takes them less time than other
comets to go around the Sun. Comets from
the Oort Cloud take as long as 30 million
years to complete one orbit and are therefore
called long-period comets. There are about a
trillion comets in the Oort Cloud. The Oort
Cloud itself is at the edge of the solar system,
almost a quarter of the way from the Sun to
the next star, Proxima Centauri.
Regular visitor
Halley’s Comet orbits
around the Sun once
every 76 years, and is
the most famous comet
in human history.
Try these too…
The Sun (10–11),
The Planets (12–13),
Humans in Space
(24–25), Earth’s
Atmosphere (26–27),
Scientific Revolution
(150–151), Forces and
Motion (190–191)
23
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Universe
Humans in Space
Ever since ancient times, humans have wanted to know more
about the skies above them. They invented stories to explain the
presence of the stars, the Moon and the Sun. Today, advanced
technology helps us to travel into space and expand our
knowledge about the world beyond our planet.
Q How do space shuttles fly into space?
A A space shuttle consists of two rocket
First woman in space
Valentina Tereshkova was
the first woman in space,
aboard Vostok 6 on
16 June 1963.
Quick Q’s:
1. What was the
first living being to
orbit Earth?
The first creature to
orbit the Earth was
a dog named Laika,
aboard the Russian
spacecraft Sputnik 2
on 3 November 1957.
2. Who was the first
person in space?
On 12 April 1961,
Russian cosmonaut
Yuri Gagarin was the
first person to travel
in space, aboard the
spacecraft Vostok 1.
Gagarin orbited the
Earth once on this
historic flight, which
lasted 1 hour and
48 minutes.
3. Which was the first
ever space station?
Salyut 1 was the first
space station. It
was launched on
19 April 1971.
24
boosters, three engines, an external fuel tank
and two smaller fuel tanks. It also has an
orbiter, which puts the shuttle into orbit.
The rockets are used to propel the shuttle
into space. When the shuttle is about 45
kilometres (28 miles) high, the rockets fall off
into the ocean and the three main engines
of the shuttle take over. Just before the shuttle
goes into orbit, its engines are shut down and
the external fuel tank is discarded.
Q Why can’t I fly into space in
an aeroplane?
A All objects, even aeroplanes, are glued
to the surface of the Earth by gravity. If you
wanted to escape this unseen force, you would
have to travel at a speed of at least 40,000
kilometres per hour (25,000 miles per hour).
Only space shuttles are designed to achieve
this speed. A mixture of liquid hydrogen fuel
and liquid oxygen is burned under high
pressure to help the shuttle’s rockets reach
this speed and push it out of the Earth’s
atmosphere into orbit.
Weightless games
On board a spacecraft, astronauts dance in zero gravity,
as one colleague holds down a keyboard to play it.
Q Is there no gravity in space?
A All objects in space exert some
gravitational force on each other. However,
the gravitational force exerted by some
objects, like the Moon, is much less than that
of the Earth. When humans are in space they
float around in the air, because there is
not enough gravity to keep their feet on
the ground.
Take off
These three images show the space shuttle at its base
(left), at the moment of take off (centre) and on its way
to space (right).
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Humans in Space
Q Could I see the Sun rise and set
from space?
A
Astronauts aboard a space shuttle
orbiting the Earth actually see 16 sunrises
and sunsets every day! This is because
once in orbit, a space shuttle goes
around the Earth at a speed of more
than 28,000 kilometres per hour
(17,400 miles per hour) and takes
only 90 minutes to complete one orbit.
Q Is it possible to live in space?
A Today astronauts spend a great deal
of time in space stations. A space station is
a floating space base. It is like a spaceship
designed so that astronauts can live in outer
space for weeks, months or even years at a
time. Unlike a spacecraft, a space station
cannot take off or land on planets. Other
vehicles are used to transport people and
materials to and from the station. Space
stations are used for studying the effect of
long-term space flights on the human
body as well as for space research.
Q
Is sending humans into space the
only way to learn more about it?
A Apart from sending
astronauts into space, we also use
satellites, probes and telescopes to
study space. Like moons, man-made
satellites revolve around planets and help
us learn more about them. A probe is an
unmanned spacecraft sent into space to study
objects other than the Earth. We have even
put huge telescopes into orbit. The Hubble
Space Telescope, sent into orbit in 1990, is
the best-known among these. It is better to
have a telescope in space than on Earth,
because then there is no atmosphere to
distort the image received by the telescope.
However, the biggest telescopes are too big
to be sent to space.
Many sunrises and sunsets
When astronauts are on board a spacecraft and orbiting
the Earth, they are moving much faster than the Earth, so
they can see the Sun rise and set many times in a day. The
normal human biological cycle can be upset by this, so
astronauts are given special medicines to help them sleep.
Try these too…
The Planets (12–13),
The Red Planet (16),
The Moon (20–21)
Looking back in time
The Hubble Space Telescope works
like a time machine that can travel
into the past. It took pictures of
the universe when it was barely a
billion years old – the universe is at
least five billion years old now, though
some scientists put its age as high as 14
billion years. The Hubble Space
Telescope can look into the past
because it takes billions of
years for light from
the far ends of the
universe to reach
the telescope. When
the light reaches it
an image is captured,
and we can see what
happened in that particular
part of the universe long ago.
25
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Planet Earth
Earth’s Atmosphere
The protective blanket of air that covers the Earth is called the
atmosphere. The Earth’s atmosphere not only prevents too
much heat from entering the planet, but also protects us from
asteroids and meteors. The Earth’s gravity helps hold the
atmosphere in place.
1. What is a barometer?
A barometer is used to
measure the pressure
in the atmosphere.
When the pressure is
high, the weather will
be fine, sunny and still.
When it is low, the
weather will be stormy.
When the pressure
increases the liquid in
the barometer is
squeezed and when the
pressure decreases it is
released. This change
is recorded.
The exosphere is the
final layer of the
Earth’s atmosphere. It
extends way into outer
space. The air in the
exosphere is very thin,
but the temperature is
very high, because the
Sun’s rays shine
directly on it.
3. Why is the ozone
layer important?
The ozone layer is
important because it
stops harmful
ultraviolet rays from
the Sun from reaching
the Earth. If the rays
are allowed through
the atmosphere, they
can cause severe health
problems like skin
cancer. Chemicals
called CFCs have made
a hole in the ozone
layer above the North
and South Poles.
26
Earth’s atmosphere?
A The Earth’s atmosphere is composed of
many gases. Nitrogen is the main gas found
in the atmosphere. It accounts for about 78
per cent and oxygen makes up 21 per cent.
The remaining one per cent is a combination
of carbon dioxide and water vapour. There
are also very small amounts of trace gases like
neon and helium that go to make up the
Earth’s atmosphere.
Quick Q’s:
2. What is the
exosphere?
Q What are the gases that make up the
Long way out
The outer layers of the atmosphere extend far
into space.
Q
What is the significance of the
troposphere in the weather pattern?
A The troposphere is the layer closest
Q
How many layers does the Earth’s
atmosphere have?
A The Earth’s atmosphere is composed of
several layers. These include the troposphere
and the stratosphere. Each layer is divided
according to the temperature and density of
air in that layer.
to the Earth’s surface, and it is here that
weather is created. Air in the troposphere
rises and falls, helping to form clouds, rain
and snow. This layer stretches about 8–14.5
kilometres (5–9 miles) above sea level.
A warm blanket
The Earth is protected by layers of gases. SOHO sends
information about these layers back to Earth.
Reflected radiation
by atmosphere
Reflected radiation
by Earth’s surface
Infrared radiation
emitted by Earth
Absorbed
radiation
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Earth’s Atmosphere
When the Earth gets hotter
The atmosphere protects us from the Sun’s heat by reflecting
a lot of it back into space. However, some gases in the
atmosphere trap some of this heat, keeping the Earth warm
even at night. This process is called the greenhouse effect
and the gases that cause it are known as greenhouse gases.
These gases include water vapour, carbon dioxide, and CFCs.
Humans are adding carbon dioxide and CFCs to the atmosphere
all the time. Too much heat is being trapped, and the Earth is
getting warmer. Global warming is leading to the melting of
glaciers and polar ice caps and an alarming rise in sea levels.
It will change the Earth as we know it.
Dangerous additions
The pollution of the atmosphere by factories and
vehicles is creating a dangerous hole in the protective
ozone layer above the Earth and increasing the Earth’s
temperature. It also makes people fall ill more often.
Q How does the stratosphere help us?
A The stratosphere is the layer just above
the troposphere. It extends upwards from
the troposphere to about 50 kilometres
(31 miles) above the Earth’s surface.
Compared to the troposphere which is full
of moisture, the stratosphere is dry. The
stratosphere contains the ozone layer. Ozone
absorbs harmful ultraviolet rays from the sun.
Q
Is the temperature the same in the
different layers of the atmosphere?
A The temperature in the
troposphere is between -52
and 17 °C (-62 to 62 °F). The
temperature in the stratosphere
is about -3 °C (26 °F). The
next layer up, called the
mesosphere, is very cold. The
temperature here is as low as 93 °C (-135 °F). In the outer
layers of the atmosphere the
temperature starts to rise again,
because there is more heat from the
Sun. Temperatures in the outer layer
can be as high as 1,727 °C (3,140 °F).
Try these too…
South Pole
Expanding hole
Seasons and Climate
(28-29), Origin of Life
(88-89), The Poles – The
Arctic and Antarctica
(122-123), Light (180181), Communication
and Satellites (192-193)
A hole above our heads
For over 20 years, scientists have noticed an
expanding hole (seen here in pink over the South
Pole) in the ozone layer above each of the poles.
This is due to the increasing use of chemicals that
go into our refrigerators and aerosol cans.
The hole means we have less protection from the
ultraviolet rays of the Sun. These harmful rays can
cause skin cancer.
27
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Planet Earth
Seasons and Climate
The Earth not only orbits the Sun, but also rotates on its own
axis as it does so. The Earth’s axis is in fact tilted – meaning that
neither of the Earth’s poles faces the Sun directly. This tilted
axis is responsible for weather and different climates.
Quick Q’s:
1. What causes day
and night?
The Earth turning on
its axis is responsible
for day and night. At
any time, half the
Earth faces the Sun,
where it is day, and
half faces away, where
it is night.
2. Does the Sun really
rise in the east?
The Earth spins in an
eastward direction.
This makes the Sun
appear as if it is rising
in the east and setting
in the west.
3. Why are days longer
in summer and shorter
in winter?
The angle at which
sunlight falls on a
particular area
determines the length
of day and night in
that region. During
summer the Sun stays
above the horizon
longer, making the
days longer.
4. What is the Coriolis
effect?
The wind moves to the
right in the northern
hemisphere and to the
left in the southern
hemisphere. This is
called the Coriolis
effect. It is caused by
the Earth’s rotation. It
is mainly responsible
for thunderstorms
and hurricanes.
28
Q How is weather different from climate?
A Sunlight falls at varying angles onto
the Earth’s surface, heating up each of its
regions differently. The difference in
temperature eventually leads to different
types of weather. A climate is when particular
weather conditions prevail in a place for an
extended period of time. So we can talk
about the weather tomorrow or this month,
but when we talk of climate we are talking
of much longer time periods – decades or
even centuries.
Q What is a season?
A Each season is a period within a year
defined by distinct weather. The tilt in the
Earth’s axis is responsible for seasons. In
temperate and polar regions four seasons are
recognized – spring, summer, autumn and
winter. Some tropical and subtropical regions
have a rainy season (sometimes called a
monsoon season) and a dry season, while
others have hot, rainy and cool seasons.
Q What are the factors that influence
weather on the Earth?
A Temperature, rainfall, wind, cloud and
atmospheric pressure are the main factors
that influence weather patterns across the
world. Wind is caused by the unequal heating
of the Earth’s surface. When the air above
a certain region becomes warm and light, it
rises and the heavier cool air sweeps across
from another area to take its place. This
movement of air is called wind. Atmospheric
pressure also affects the movement of wind,
which always flows from a region of high
pressure to that of low pressure. The
difference in pressure between the two areas
determines the speed with which the wind
blows. If there is a small difference, we feel
a breeze. If the difference is large, it leads
to a storm. If the wind is flowing over a large
water body such as a sea, it can pick up
moisture and carry clouds and rain with it.
Low pressure usually means stormy weather
and rain, while high pressure usually means
lots of sun and not much wind. There are
other factors, such as the ocean currents
created by the Earth’s rotation, which also
influence weather.
The blowing wind
The wind always blows from an area of high pressure to
an area of low pressure.
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Seasons and Climate
Q How are clouds formed?
A The Sun’s heat causes water in the
Water stored in
Snow melts ice and snow
down to
Precipitation
streams
oceans, rivers and lakes to evaporate and
form water vapour. The warm water vapour
rises upwards, and as it rises, it cools down.
As a result, the water vapour in the air
condenses to form clouds containing tiny
droplets of water. These droplets grow
larger in size and finally fall down as rain.
Sometimes, the temperature is so low that
these droplets freeze into ice crystals and
fall down as snow.
Condensation
Water stored in
the atmosphere
Transpiration
Evaporation
Water stored in
oceans
The water cycle
All the water in the Earth’s atmosphere, both on its
surface and underground, is a part of the water cycle.
The water is recycled again and again.
Solstices and equinoxes
Cold places
The closer you are to the North or South Pole,
the colder it is. Some animals have adapted so
they can survive in the freezing temperatures.
Q Which is the place on the Earth that has
the coldest climate?
A
The climate of Antarctica is the coldest
on Earth. Nearly all of Antarctica is covered
with an ice sheet about 2.5 kilometres thick.
The lowest temperature recorded on this
continent is -89.6 °C (-128.56 °F) at Vostok
research station at the centre of the East
Antarctic Ice Sheet.
In the northern hemisphere the
longest day falls during the summer,
on 21 June, when the northern half
of the Earth is tipped towards the
Sun. This is known as the summer
solstice. In the extreme north the
Sun does not set at all during this
period. During the winter solstice
(22 December), the northern part
of the Earth is tipped away from the
Sun, resulting in the longest night
of the year. On 23 September and
21 March the Earth is positioned in
such a way that the length of day and
night is equal (12 hours each). These
days are known as the autumnal and
spring equinoxes respectively.
Try these too…
Earth’s Atmosphere
(26–27), Plant Life
(96–97), South America
(112–113), Australia and
Oceania (114–115),
Africa (118–119), Asia
(120–121), The Poles –
The Arctic and Antarctica
(122–123), Scientific
Revolution (150–151)
29
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Planet Earth
Mountains, Valleys and Caves
Mountains are formed when two of the continental plates that
make up the Earth’s crust collide. The force caused by the
collision pushes both plates (also called tectonic plates) upwards,
creating a mountain. Valleys and caves are also natural features
created by erosion and the movement of the Earth’s crust.
Q Can we live on mountains?
A It is not easy to live on high mountains.
Quick Q’s:
The weather is extremely cold and not
suitable for farming. At very high altitudes,
oxygen levels are so low that it becomes
difficult to breathe without an oxygen tank
and mask.
1. Which is the highest
mountain peak in the
world?
Q How are mountains different
Climbing mountains
Scientists climb mountains
to study them.
At a height of about
8,848 metres (29,028
feet) above sea level,
Mount Everest is the
highest peak in the
world. It is a part of the
Himalayan mountain
range that was formed
about 10–15 million
years ago.
2. How big is the
Grand Canyon?
The Grand Canyon is
about 446 kilometres
(277 miles) long and
roughly 1.6 kilometres
(1 mile) deep. It is
made up of several
layers of rock, each
one older than the
one above it.
3. How are glacial
valleys formed?
When glaciers slowly
flow downhill, they
collect many pieces
of rock on the way.
These pieces scrape
against the valley floor,
digging deeper into
it, until a U-shaped
valley is formed.
30
Q How is a valley formed?
A A valley is a low-lying area of land that
is usually found at the foot of mountains
or hills. The most common way valleys are
formed is by the erosion of land from
running water. River valleys are formed by
the action of the river. As a river flows
downhill, it cuts through the land like a
knife. Over thousands of years the river
erodes the land to form a valley, usually in
the shape of a V. In contrast, valleys formed
by glaciers are often U-shaped, because they
are formed by rocks carried in the glacier
that erode the soil.
Plate 1
Mountains
Plate 2
from plateaus?
A Like a mountain, a plateau is higher
than its surrounding area. However, plateaus
have a flat top, while mountains have peaks.
Like mountains, plateaus are formed when
two continental plates collide, but erosion
due to wind and water flattens the top.
Plateaus are not as tall as mountains. In fact,
some plateaus, such as the Tibetan Plateau,
lie between two mountain ranges.
Forming a mountain
Mountains are formed when two of the Earth’s tectonic
plates collide. The crust is forced up between the two
plates, giving birth to the mountain range.
U-shaped valley
Glaciers carry stones that scour out the soil, forming
U-shaped valleys. Rivers, in contrast, usually form
V-shaped valleys.
Q What is a canyon?
A A deep valley with cliffs on both sides is
called a canyon. Sometimes a large river may
run through a canyon. The Grand Canyon in
Arizona, USA is the world’s largest canyon.
It was formed by the Colorado River. Millions
of years ago, this region was covered by sea.
Slowly, a part of the sea floor was pushed up
to form a plateau. Over the years, rainwater
collected to form a river. This river cut into
the rocks on the plateau to form the canyon.
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Mountains, Valleys and Caves
Caves of lava
When volcanoes erupt, lava flows down
the side of the volcano. The surface of
the lava cools and becomes solid, while
hot lava continues to flow underneath it.
Once the eruption is over, there is a
hollow tube, or cave, left behind
underneath the hard crust of lava.
Q What are caves?
A Caves are huge holes under the ground,
in cliffs or under the sea. Caves can be
formed in many ways. Most rock caves,
especially limestone caves, are formed by
rainwater that seeps into tiny cracks in the
rocks. The rainwater contains minerals and
chemicals that slowly causes the rock
to dissolve, leaving behind a large hole.
This process may take several thousand, or
even a few million years.
Q How are sea caves formed?
A Sea caves are formed by waves that
wear away the rocks at the base of a cliff.
These rocks are usually very weak and
have tiny cracks in them. The continuous
pounding of the waves causes the tiny
cracks to widen and soon the rocks begin
to crumble and form small hollows.
These hollows keep expanding as sand,
gravel and rocks brought by the waves erode
their inner walls. Some sea caves are
submerged during high tide and can only
be seen when the water goes down at low tide.
Q What is a rift valley?
A A rift valley is created when two tectonic
plates pull away from each other, leaving a
low space in the middle. The Great Rift Valley
is the best known rift valley in the world. It
covers a distance of over 6,000 kilometres
(3,700 miles), stretching from northern Syria
in West Asia to central Mozambique in East
Africa. It began to form about 35 million
years ago, when the African and Arabian
tectonic plates began to pull apart.
Even today it is still growing, as East Africa
slowly separates from the rest of Africa.
Rift in the Earth
When two of the Earth’s plates
move away from each other, the
soil covering them falls down
and forms a rift valley. The rift
valleys in East Africa now form
a series of lakes.
Normal
Faults
Sea cave
Sea caves are most
common in areas where
the rocks on the coast
are soft.
Try these too…
Other Landforms
(32–33), Volcanoes
(36–37), Earthquakes
and Tsunamis (38–39),
South America
(112–113), Australia
and Oceania (114–115),
Africa (118–119), Asia
(120–121)
Earth’s Crust
Mantle
31
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Planet Earth
Other Landforms
Rivers, lakes and streams are natural bodies of water that
are found across the world. When it rains or when snow on
mountains melts, the water flows down the slopes, forming
streams. Several streams join together to form a river. Small
rivers drain into larger rivers. The water in rivers keeps flowing
until it reaches the sea, though a few rivers hit very dry desert
land and dry up.
Quick Q’s:
1. Which is the largest
freshwater lake in
the world?
Lake Superior, one of
the Great Lakes of
North America, is the
largest freshwater lake
in the world. This lake
is over 560 kilometres
(350 miles) long and
about 257 kilometres
(160 miles) wide.
2. What is the Sahara
known for?
The Sahara is the
largest hot desert in
the world. Located
in Africa, it spreads
across Mauritania,
Morocco, Mali, Algeria,
Tunisia, Niger, Libya,
Chad, Egypt, Sudan
and Eritrea.
3. Which is the
longest river?
The Nile is the longest
river on Earth. It flows
for 6,695 kilometres
(4,184 miles).
4. Why is Lake
Baikal special?
Lake Baikal in
southern Siberia is
the deepest lake in
the world, with a
maximum depth
of 1,637 metres
(5,371 feet). It has
been around for
almost 30 million years.
32
Largest freshwater lake
Lake Superior in North America is the largest
freshwater lake in the world by area and the
third largest by volume.
Q How are lakes formed?
A Sometimes, rainwater collects in big
hollows in the ground to form lakes. These
hollows can be formed by the movement
of the plates that make up the Earth’s crust,
or by moving glaciers. Lakes are also formed
by landslides that leave huge depressions in
the ground. Most lakes and rivers contain
freshwater. In places containing a large
amount of salt, lake water can be salty.
View from space
This photograph, taken
from an artificial satellite,
shows Lake Baikal in
southern Siberia. The size
of the lake has been
reduced in recent years,
as more and more of its
water is taken away
for irrigation. It is
considered to be one of
the most serious problems
in the region.
Q What are waterfalls?
A Sometimes the surface over which a river
flows drops suddenly. Then the water flows
over to form a waterfall. There are different
kinds of waterfalls. A cascade waterfall flows
down a series of natural rock steps. There
are no steps in a free-falling waterfall. In a
fan waterfall, the water spreads out as it falls
down. Angel Falls in Venezuela is the highest
free-falling waterfall in the world. The water
falls 807 metres (2,648 feet) without any
interruption. Often, the sunlight falling over
a waterfall creates a rainbow.
Q Do rivers flood?
A Yes, they do. Rivers often overflow their
banks and flood the land around them. This
can happen when there has been a lot of rain
or a lot of snow has melted in the mountain
where the river starts its journey. Floods are
often very destructive. They can damage
crops and houses and kill people. But in the
long run they can also do some good. They
bring fresh soil down the river and spread it
on the flooded land. Egyptian farmers have
been dependent on the annual flooding of
the Nile for thousands of years. The Amazon
and the Ganges rivers regularly bring fertile
soil to the agricultural areas downstream.
Longest river
The ancient civilization of Egypt started along the
banks of the Nile.
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Other Landforms
Try these too…
North America
(110–111), South
America (112–113),
Australia and Oceania
(114–115), Europe
(116–117)
Largest desert
The Sahara is the world’s
largest hot desert. It
spreads right across
northern Africa from
the Atlantic Ocean in
the west to the Red Sea
in the east. Sand and
rock cover most of the
dry Sahara, but there are
oases where people have
lived for centuries.
Q What is a desert?
A A desert is a dry region with very little
rainfall. During the day, temperatures can rise
above 50 °C (122 °F). However, nights in a
desert can be extremely cold. Most deserts
are covered with sand and rocks. Animals and
plants that live in this habitat are specially
adapted to life with little water and extreme
changes in temperature.
Cold desert
Most deserts are hot during the day, but some deserts
are in the coldest parts of the Earth. Some cold deserts are
covered in ice throughout the year, allowing very few plants to
grow. Cold deserts are also not very suitable for animals. Few
species can survive such extreme cold for long periods
of time. Antarctica is the largest cold desert in the world.
Patagonia in the southernmost part of South America and
Gobi in Mongolia are also cold deserts.
Q What are montane deserts?
A Some deserts, located at very high
altitudes, are known as montane deserts. They
are common in the Himalayas. Some, like the
Tibetan Plateau, are relatively flat. Very few
animals can survive the extreme cold and
dryness, but the yak lives in Tibet.
Q What is an oasis?
A For most part deserts are dry and have
no water bodies. However, small springs with
trees and plants growing around them can
be found in certain places. These isolated
regions are called oases. An oasis is vital for
all forms of life in the desert.
33
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Planet Earth
Oceans
Arctic Ocean
Oceans occupy about 70 per cent of the Earth’s surface. There
are five oceans in the world. They are the Atlantic, Pacific,
Indian, Arctic and Antarctic oceans. The surface under the
oceans is called the ocean floor. Like land, the ocean floor also
has natural features like plains, valleys and mountains.
Atlantic
Ocean
Indian
Ocean
Pacific
Ocean
Antarctic Ocean
Quick Q’s:
Q Which ocean is also known as the
1. Which is the largest
of all oceans?
Southern Ocean?
The Pacific Ocean is
the world’s largest and
deepest ocean. It has
an average depth of
over 4,000 metres
(13,100 feet). It has the
world’s deepest trench
– the Mariana Trench
near Japan. The
Challenger Deep in the
Mariana Trench is the
deepest point on Earth
– about 11,033 metres
(36,200 feet) deep.
A
2. What causes an
ocean current?
An ocean current is
a mass of water that
keeps moving in one
direction. Surface
currents are caused by
wind and the Earth’s
rotation. Underwater
currents are the result
of differences in
temperature and salt
content of the water.
3. What is a
black smoker?
When water seeps into
the crust of the ocean
floor through cracks, it
may be heated by the
magma below. As
pressure builds up
within the crust, the
hot water shoots up
through these cracks.
These jets of warm
water are often black
due to their mineral
content, so they are
called black smokers.
The Antarctic Ocean is also called the
Southern Ocean. Until recently, the Antarctic
Ocean was considered to be a part of the
other main oceans, as it was actually formed
from parts of the Pacific, Atlantic and Indian
oceans. In the year 2000, however, it was
officially named the ‘Southern Ocean’.
Island Arc
Q What is the ocean floor like?
A The ocean floor is far from flat. The
edges of islands and continents gently slope
into the surrounding water to form an area
called a continental shelf that is higher than
rest of the ocean floor. A continental shelf
usually extends about 75 kilometres (47 miles)
out to sea but some, like the Siberian shelf
in the Arctic Ocean, can extend up to 1,500
kilometres (932 miles). The continental shelf
contains large deposits of petroleum, natural
gas and minerals. It also receives the most
sunlight, so marine life thrives here. The
point where the continental shelf starts to
plunge steeply towards the deep ocean floor
is called the continental slope. It is here that
the deep canyons of the ocean are found.
N. Equatorial
N. Equatorial
N. Equatorial
S. Equatorial
S. Equatorial
S. Equatorial
West Wind Drift
34
Oceans of the world
The five oceans of the world cover over 70 per cent of
the surface of the Earth.
Active Volcano
Oceanic Trench
Not a flat floor
The ocean floor has mountains and valleys. Some of the
mountains are tall enough to rise above the surface and
form islands.
Q
What causes the formation of mountains
and valleys on the ocean floor?
A
Like the rest of the Earth, the ocean
floor is divided into tectonic plates. The
movement of these plates is responsible for
features like ridges, trenches, and valleys.
Ridges are formed when two plates drift
apart. Boiling rock from inside the Earth,
called magma, oozes out through the cracks
between the plates and cools to form a ridge.
Trenches are formed when a heavier plate
sinks down under a lighter one.
Ocean currents
The water in the oceans and seas is always in motion,
due to the rotation of the Earth, the gravitational pull
of the Sun and Moon, and the difference in temperature
and salt content of the water. These movements form
strong currents in the oceans, both at the surface
and deep down.
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Oceans
Q What is a mid-ocean ridge?
A The ridges on the ocean floor are
Q How are waves different from tides?
A Waves are caused by wind, while tides
connected to form a single chain called a
mid-ocean ridge. The mid-ocean ridge is over
80,000 kilometres (50,000 miles) long and is
the longest mountain chain on Earth. On
average, these mountains lie about 2,500
metres (8,200 feet) below the ocean surface,
with their peaks sometimes breaking above.
are the regular rise and fall of the ocean’s
surface caused by the gravitational pull of the
Sun and the Moon on the water that is in the
ocean. Waves are formed when winds blow
over the surface of the ocean. Stronger winds
create larger waves. The water in a wave
normally moves in circles. As a wave
approaches the land it is slowed down by the
rising slope of the seabed. But it is the
bottom portion of the wave that is slowed
down. The top part of the wave keeps moving
and crashes on to the shore as a breaker.
North American
Plate
Eurasian
Plate
Iceland
Atlantic Ocean
Mid-Atlantic
Ridge
Mountains
down there
The mid-ocean
ridge exists on
the floor of all
the oceans in the
world. The diagram
shows a part of the
mid-Atlantic ridge,
which extends
below Iceland.
Many volcanoes lie
along the ridge.
Q How are volcanic islands formed?
A Volcanoes under the sea are responsible
for the formation of volcanic islands. As
magma keeps oozing out of a volcano, it can
collect, causing the volcano to grow and rise
above the ocean surface as an island.
Q What is special about the Hawaiian
Beach
Try these too…
Volcanoes (36–37),
Earthquakes and
Tsunamis (38–39),
Hurricanes and
Tornadoes (40–41),
Whales (56–57),
Seabirds (60),
Sharks and Rays (68–69),
Life of a Fish (70–71),
Electricity (186–187)
The breaker
Breakers are higher when
the seabed slopes down
quickly from the shore.
The beaches of Hawaii and
Australia are famous for
their high breakers.
Surf
Deep water
Feeling the heat
The temperature of the water from an underwater hot spring
can be as high as 400 °C (752 °F). However, this water is rich
in minerals, helping some unusual creatures like giant
tubeworms and eyeless shrimps survive in an environment
where nothing else can live.
group of islands?
A
Volcanic activity does not always take
place near plate boundaries. There are some
places deep inside the Earth that are much
hotter than others. As a result, there is
constant volcanic activity above these spots,
known as hot spots. This activity leads to the
formation of underwater volcanoes. The
constant movement of tectonic plates
eventually shifts the volcano away from the
hot spot. Soon, another volcano is created
in the area near the hot spot. This often
leads to the formation of a chain of islands,
such as the Hawaiian Islands.
35
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Planet Earth
Volcanoes
A volcano is a mountain through which molten rock and gases
erupt from the Earth’s crust. Volcanoes are named after the
Roman god of fire, Vulcan.
Q How are volcanoes formed?
A Volcanoes are formed by tectonic plates
Volcanic rocks
Hardened lava from
volcanoes forms new rocks.
Quick Q’s:
1. Which is the highest
volcano on Earth?
Mauna Loa in Hawaii is
the highest volcano on
Earth. It rises about 4
kilometres above sea
level; below that, it
extends to 5 kilometres
down before it reaches
the seabed. Its massive
weight has pushed the
volcano down a further
8 kilometres below the
seabed! So Mauna Loa
is 17 kilometres
(56,000 feet) from its
base to its summit.
2. Which is the most
active volcano?
colliding with each other. The heavier plate
is usually forced down below the lighter one,
where part of it is melted by the heat of the
crash. The melting plate forms magma
or molten rock that collects below the surface
of the Earth in magma chambers. As the
amount of magma increases, the pressure
inside the chamber rises. This creates
a mountain, or volcano. The volcano has a
cone, from which gases and lava may trickle
out. When the pressure gets too high, the
whole chamber explodes, ejecting the
magma. This is a volcanic eruption.
Continental
Crust
Oceanic Crust
Mantle
Mount St Helens in
Washington State of
USA is the most active
volcano. It last erupted
in 1980.
Movements of the Earth
The tectonic plates that cover the Earth can move in
various ways, and are constantly rubbing against one
another, sometimes violently.
3. What are geysers?
Q What are the various things that happen
Geysers are jets of hot
water that erupt from
the Earth. When water
trickles down into the
hot molten rock under
the Earth’s crust, it is
heated up. As the water
becomes hotter, the
pressure builds up,
finally causing it to
spurt out.
36
during a volcanic eruption?
A Magma, or molten rock, erupts through
the surface of Earth during an eruption.
Magma that comes out is called lava. It can be
thick and slow moving or thin and fast. Pieces
of rocks and ash also erupt from the volcano.
Pumice stone, a light rock full of air bubbles,
is formed in an explosive volcanic eruption.
These volcanic materials are called pyroclasts.
Hot water
Old Faithful is a geyser of hot water in the Yellowstone
National Park, USA. It erupts from the Earth every
90 minutes, on average.
Q Do volcanoes erupt regularly?
A Volcanoes may be active, intermittent,
dormant or extinct depending on how often
they erupt. Active volcanoes erupt often.
Intermittent volcanoes erupt at regular
intervals. Dormant volcanoes have been
inactive for a long time. They are the most
dangerous because they are merely ‘sleeping’
and can erupt without warning. Extinct
volcanoes have not erupted for thousands of
years. It is difficult to distinguish between
dormant and extinct volcanoes because some
volcanoes may remain quiet for a long time
before suddenly becoming active again.
Active volcano
Mount St Helens is the most active volcano in the world.
It last erupted in 1980.
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Volcanoes
Q What are the different types of volcanoes
on the Earth?
A
Volcanoes are classified according to
their shapes and the type of material they
are composed of. A shield volcano is a gentle
sloping volcano that has long-lasting, gentle
eruptions. Most of the volcanoes in the
Hawaiian islands are shield volcanoes. A strato
volcano is a steep volcano shaped like a cone.
When it erupts, it emits gases, ash, pumice
and lava. These volcanic eruptions are
accompanied by deadly mudflows, making
strato volcanoes the most dangerous among
the volcanoes on Earth. Famous strato
volcanoes include Mount Vesuvius in Italy and
Mount Fuji in Japan.
Ring of Fire
Q What is the ‘ring of fire’?
A The area encircling the Pacific Ocean is
called the ring of fire because most of the
Earth’s active volcanoes are located in a ring
around it. The massive Pacific plate is
expanding continuously at the edges of the
ocean and hitting the other smaller plates
next to it. The collisions cause frequent
volcanic activity and earthquakes. The ring of
fire stretches from New Zealand, along the
eastern coastline of Asia and along the western
coast of North and South America.
Ring of fire
The ring of fire around
the Pacific Ocean has
been responsible for some
of the most destructive
volcanic eruptions and
earthquakes in human
history, including the
1906 San Francisco
earthquake and the
1995 earthquake in
Kobe, Japan. The biggest
earthquake ever recorded
was also in the ring of
fire – the Great Chilean
earthquake of 1960, 9.5
on the Richter scale.
Try these too…
The Hot Planet (14),
The Red Planet (16),
Oceans (34–35), Origin
of Life (88–89),
Dinosaurs (90), North
America (110–111),
South America
(112–113), Australia and
Oceania (114–115),
Europe (116–117),
Africa (118–119), Asia
(120–121), The Poles –
The Arctic and
Antarctica (122–123),
Ancient Americas (132)
An island disappears
The cone shape
The cone-shaped volcano, known as a strato volcano,
may be the most famous, but is only one of many
types of volcanoes.
One of the largest volcanic eruptions recorded in recent history
occurred on the island of Krakatau in Indonesia in 1883. The
eruption was so massive that most of the island disappeared
into the sea (pale blue area between the two small islands).
Over much of the world, the sky was dark with ash for days.
Q Are there volcanoes under the sea?
A Volcanoes form under the sea in the
same way as on land. When two oceanic plates
collide, one may get pushed under the other.
The heat generated by the crash causes one
plate to melt and form magma. The hot
magma rises and forms an underwater
volcano, just as it does on land. The Vailulu
volcano in Ta’u Island in the Pacific Ocean is
an underwater volcano.
37
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Planet Earth
Earthquakes and Tsunamis
The Earth is made up of a boiling hot, liquid centre covered by
a crust. This crust is broken into pieces called tectonic plates,
which move around, sometimes colliding into each other. These
collisions lead to earthquakes, some so small that they are hardly
felt. But some earthquakes are so massive that they cause the
ground to shake violently, destroying houses and killing people.
Quick Q’s:
1. Which is the worst
earthquake in history?
In 1556, an earthquake
struck three provinces
in China. About
830,000 people were
killed in the disaster.
It was the worst
earthquake in history.
2. Can we predict
earthquakes?
No, we cannot. The
movements of the
Earth are too complex
for us to be able to
predict earthquakes.
But we do know the
lines along which the
Earth’s plates meet,
so we know the areas
that are more likely
to have earthquakes.
3. What is liquefaction?
Liquefaction is caused
by the violent shaking
of the ground during
an earthquake. Moist
soil or sand turns into
slurry, like quicksand.
This liquid can suck in
entire buildings.
4. Is a tsunami the
same as a tidal wave?
A tsunami is diffeerent
from a tidal wave.
A tidal wave is
generated by high
winds, but a tsunami is
caused by underwater
earthquakes, landslides
or volcanic eruptions.
38
Q Do earthquakes occur everywhere?
A Earthquakes usually occur along a region
called a fault, where broken rocks under the
Earth’s surface rub against each other and
cause tremors. Faults are marked by cracks on
the Earth’s surface, caused by the movement
of tectonic plates. Most faults are located near
the edges of the plates, but small faults can be
found far away from the boundaries.
Q How do faults produce earthquakes?
A Faults allow the rock fragments that form
the Earth’s crust to move about. Over a
period of time, plate movement builds up
pressure, causing rocks along a fault to bend
or break with a jolt. This sudden movement
releases energy that moves through the surface
of the Earth in the form of waves. This is an
earthquake. The energy moves out in a circle
from the point where the movement occurs.
Fault in the Earth
The San Andreas Fault in
California, USA, is one
of the few faults in the
Earth’s surface that can
actually be seen by any
observer on the ground.
Most of the other faults
are covered by soil or
water. These faults mark
the lines on the Earth’s
surface where two
tectonic plates of the
Earth meet. As a result,
areas around these faults
are the ones most prone
to volcanic activity
and earthquakes.
San Francisco 1906
The notorious San
Francisco earthquake
in 1906 destroyed
most of the large
buildings in the
city. Tramlines
were ripped up
as the roads
buckled
under
them.
Q Where is an earthquake most dangerous?
A The point inside the Earth where the
rocks first begin to break is the focus of the
earthquake. The point on the Earth’s surface
that lies directly above the focus is called
the ‘epicentre’. This is where the earthquake
is strongest. In a major earthquake, the
maximum damage takes place at the
epicentre, and there is less damage as you
get further away from it. The epicentre is
directly above the hypocentre, the actual
location of the energy released inside the
Earth. Seismic waves ripple out from the
hypocentre. After an earthquake, scientists
can find the centre by looking at the seismic
wave data from three separate locations.
The extent of the damage caused by an
earthquake may also depend on the
nature of the soil.
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Earthquakes and Tsunamis
Q Do earthquakes occur only on land?
A Earthquakes also occur under the ocean.
Sometimes, massive earthquakes that start on
the ocean floor can create giant, destructive
waves called tsunamis. These waves move at
great speeds (up to about 800 kilometres or
500 miles per hour) and can travel thousands
of kilometres across the ocean. In deep water,
the waves are not very high. They gain
strength and height as they approach the
shore. Tsunamis can be about 30 metres
(98 feet) high. These huge waves break
on to the shore with a great deal of force,
bringing down trees and large buildings.
When disaster strikes
On 26 December 2004, a tsunami spread
across the Indian Ocean, killing over
250,000 people. The tsunami was caused
by an underwater earthquake that
occurred near the island of Sumatra,
Indonesia. The tsunami hit the coasts of
about 15 countries. Its effect was felt
even in the southern tip of Africa, about
8,500 kilometres (5,300 miles) away from
the epicentre of the earthquake!
Before
After
Q Do earthquakes cause destruction every
time they occur?
A Some earthquakes are extremely
destructive. A strong quake can topple
buildings and bridges, trapping people
underneath them. If gas pipes and electrical
wires break, they can start fires that rage for
several days. Earthquakes can also cause
landslides and avalanches. The violent
shaking of the Earth sometimes loosens
chunks of snow or mud that slide down
the slopes of mountains and hills, burying
houses and people under them.
Q Can an earthquake be measured?
A Earthquakes are measured using the
Richter scale. It was developed in 1935 by
Charles Richter and Beno Gutenberg at the
California Institute of Technology. This scale
uses numbers from 1 to 10 to measure the
intensity of an earthquake. Each increase
of one point on the scale means a ten-fold
increase in the strength of the earthquake.
So a level 5.0 earthquake is ten times stronger
than a level 4.0 earthquake. The Richter scale
works by measuring vibrations around the
epicentre of an earthquake.
Earthquake effect
An earthquake can lead
to a deadly avalanche or
a landslide that can cause
more damage than the
original earthquake.
Old instrument
The ancient Chinese
invented an instrument
that reacted to tremors
in the Earth – a ball
dropped from the mouth
of the dragon into
the mouth of a frog,
warning people about
a possible earthquake.
Try these too…
The Hot Planet (14),
Mountains, Valleys and
Caves (30–31), Oceans
(34–35), Volcanoes
(36–37), North America
(110–111), South
America (112–113),
Australia and Oceania
(114–115)
39
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Planet Earth
Hurricanes and Tornadoes
Sometimes the weather becomes wild. Blizzards, thunderstorms,
hurricanes and heatwaves are some examples of extreme
weather conditions. Such severe weather often causes a great
deal of damage to both life and property. Hurricanes and
tornadoes especially are very destructive.
Quick Q’s:
1. Can hurricane winds
be measured?
Hurricanes are divided
into five categories
depending on their
wind speeds. Category
5 hurricanes are the
worst, causing
maximum damage.
Winds of a category 5
hurricane can reach
speeds of about 250
kilometres per hour
(155 miles per hour).
Category 1 hurricanes
are much weaker, and
only travel at 119–153
kilometres per hour
(74–95 miles per hour).
Q What is a hurricane?
A Hurricanes are large, violent storms that
form over the ocean near the equator. These
storms are accompanied by winds that travel
at an average speed of about 119 kilometres
per hour (74 miles per hour). Hurricanes
usually occur between June and November.
3. What is the
Fujita scale?
The Fujita scale is
used to measure the
intensity of a tornado.
It ranks tornadoes by
the damage caused to
man-made structures.
4. How did tornadoes
get their name?
The word tornado is
from the Spanish tomear,
meaning ‘to turn’.
40
rises, creating an area of low pressure. Cooler
wind moves in to take place of the warm air.
The Earth’s rotation causes the rising hot air
to twist and form a cylinder. As the warm air
rises higher, it cools down and forms huge
thunderclouds and finally becomes a
hurricane. Meanwhile, the cooler air at the
bottom also becomes warm, adding more
energy to the storm.
Q What is the eye of a hurricane?
A The centre of a hurricane is called the
eye. The eye is an area of clear skies, light
winds and no rain. It is also the warmest part
of the storm and is surrounded by a wall of
heavy rain and strong winds. People faced
with a hurricane usually experience the heavy
rain and strong winds first, then there is a
period of calm as the eye passes over the area,
followed by more stormy weather.
2. What is a
storm surge?
Sometimes the strong
winds of a hurricane
can cause the water
level in the ocean to
rise. Huge waves hit
the coast along with
the storm, causing
severe flooding. This is
called a storm surge.
Q How does a hurricane form?
A When the air above the sea is heated it
Eye of the hurricane
This satellite image clearly shows the eye of the
hurricane, an area of calm in the middle of the storm.
Huge destroyer
In 2005, Hurricane Katrina, seen here in a satellite
image, destroyed large parts of the city of New Orleans
in the USA.
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Hurricanes and Tornadoes
Q What is the worst hurricane on record?
A The hurricane that ripped through the
Caribbean islands of Martinique, St. Eustatius
and Barbados in October 1780 is the worst on
record so far. It killed nearly 22,000 people.
However, this hurricane does not have a
name, because the practice of giving human
names to major hurricanes started during
World War II.
Air Current
Chasing the storm
Most of us would prefer to stay as
far away as possible from all
violent storms, especially
hurricanes and tornadoes. Some
people however, chase hurricanes
and tornadoes. For these people,
confronting a storm is exciting. Storm chasers use special
equipment to locate and follow storms. They usually have a
well-equipped vehicle fitted with the latest technology, including
cameras, radios, scanners and first-aid kits. The videos,
photographs and all other data collected by storm chasers have
helped scientists understand hurricanes and tornadoes better.
Water
Spout
The making of a storm
Warm air rises from the sea, taking water with it in the
form of a funnel, and starting a storm.
Q What is a tornado?
A A tornado is a black, funnel-shaped
storm that is highly destructive. These storms
usually form where cold polar winds mix with
warm, moist tropical winds. They start as
rotating thunderstorms called supercells.
Gradually the spinning wind in the supercell
forms the funnel of a tornado. The wind in
the funnel spins so fast that it sucks objects
into it like a vacuum cleaner.
Q What is Tornado Alley?
A Tornado Alley is an area that extends
across the Great Plains of the USA, from
central Texas in the south to the border of
Canada in the north. The conditions in this
region are most suitable for the formation
of severe tornadoes, which occur during
spring and early summer.
Q What is a waterspout?
A Tornadoes usually travel across land.
However, occasionally, tornadoes pass over
water. In these cases, the high-speed winds
suck in water, creating tall columns of
spinning water called waterspouts. These
waterspouts are weaker than land tornadoes
and occur in warm tropical oceans. However,
they are still strong enough to cause huge
damage to any boat or ship caught in them.
Waterspout
When tornadoes pass
over water, they suck
the water up into tall
spinning columns called
waterspouts.
Try these too…
Seasons and Climate
(28–29), Communication
and Satellites (192–193),
Water Transport
(196–197)
41
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The Living Planet
Monkeys
Monkeys belong to the group of mammals called primates,
which also includes apes and humans. All three species share
certain characteristics, such as narrow noses and five fingers
and toes. However, unlike apes and humans, many monkeys
have tails. Monkeys from Asia and Africa have noses that point
downwards, while monkeys from Central and South America
have broad noses and nostrils that open sideways.
Quick Q’s:
1. Why is the Japanese
macaque also known as
the snow monkey?
The Japanese macaque,
commonly known as
the snow monkey, is
one of the few primate
species that live in
cold regions. They are
found in the mountains
of Honshu in Japan.
When it is very cold,
these monkeys move
near hot springs to
keep themselves warm.
2. What is grooming?
Monkeys and apes
groom each other’s fur
using their hands. This
helps not only to get
rid of parasites and dirt
but is also an important
part of socializing.
3. Why are monkeys
called social animals?
Most species of
monkeys live in
groups. The size of
a group depends on
how much food is
available and if there
are predators around.
4. Do howler
monkeys howl?
Howler monkeys make
a peculiar barking
sound. They can
be heard up to
3 kilometres
(1.9 miles) away.
42
Q
What are the common characteristics
of primates?
A All primates have a large brain, and their
eyes face forwards, allowing binocular vision.
Most of them have thumbs on both hands
and feet that can be used for grasping.
Their highly developed brain helps
them to remember things, and to
understand others.
Q How many primate
species are there in the world?
A There are more than
350 species of primates in the
world, divided into two groups.
Small to medium-sized
primates, such as lemurs and
lorises, have long whiskers
and well-developed senses of
smell and hearing. The rest
of the primates, including
humans, apes and other
monkeys, are part of the
‘humanlike’ category. This group
consists of about 175 species.
Most of these primates have flat
faces and a poor sense of smell.
Big hug
Snow monkeys
are often found
huddling near hot
springs to keep
warm.
Top of the forest
Colobus monkeys are usually found
at the top layer of branches in
African rainforests.
Q What does a monkey eat?
A Most monkeys will eat whatever
they come across, including birds’ eggs, fruit
and the sap from plants. Several species
of monkey will even attack and eat
other monkeys. Howler monkeys
of South America and colobus
monkeys of Africa eat
the leaves of any
type of tree. The
digestive system
of leaf-eating
monkeys is similar
to that of other
herbivores, like
deer and cows.
Ringed tail
Lemurs are easily
identified by their
ringed tails.
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Monkeys
Q Why are spider monkeys so called?
A A spider monkey is a species of New
World monkey (from the American
continent) that has long, slender, spidery
limbs. It displays great acrobatic skills, using
its hands and strong tail to grip branches as it
swings through the trees. Spider monkeys
only travel on particular routes through trees,
marking the branches with their own
individual scent as they go.
Q What is a tarsier?
A Tarsiers are very different from other
monkeys. They have enormous eyes, long feet
and are active at night. Tarsiers eat insects,
but also prey on small birds, lizards and
snakes. They use their long back legs to leap
on to prey. Holding the prey with
their hands, they kill it with their
sharp, pointed teeth.
Five hands?
The spider monkey of central and South America
has a tail whose tip is so well developed it can almost
be considered a fifth hand. Each tip even has its own
unique ‘fingerprint’.
Night hunter
Tarsiers have huge eyes that help them to find prey
in the dark.
Try these too…
Apes (44-45), Venomous
Snakes (76-77), Other
Prehistoric Animals
(94-95), South America
(112-113), Africa (118119), Ancient India and
China (126-127)
Alarm calls
Monkeys use several methods of communication. A few species of
monkey that live alone use scent to communicate. Urine, faeces or
special scent glands are used to mark territory or to let other
monkeys know they are ready to mate. Monkeys that live in groups
communicate using signs and calls. Some
species, like the African vervet
monkeys, use different alarm
calls for each of their main
predators – eagles, leopards
and snakes. The monkeys
react differently to each
call. When they hear the
eagle alarm call, the
monkeys hide among dense
vegetation. At the sound of
the leopard call they climb
as high as possible.
43
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The Living Planet
Apes
Apes are primates with long arms, a broad chest, and no tail.
Early apes evolved several million years ago, long before humans.
Only six species of ape survive today. Gibbons, siamangs and
orangutans live in Asia, while gorillas, chimpanzees and bonobos
are African apes.
Quick Q’s:
1. Which species
is known as the
crying ape?
Chimpanzees are
crying apes. They
bark and produce
loud calls to warn the
rest of the group about
approaching danger.
2. Is a siamang also
an ape?
The siamang is a
black-coloured gibbon
found in Malaysia and
Sumatra. The siamang
is one of the three
species that form the
group of lesser apes.
It is the largest of the
lesser apes, growing
to a height of about
1 metre (3 feet).
3. What are bonobos?
Bonobos are a species
of chimpanzee,
discovered in 1928 by
American scientist
Harold Coolidge. They
are the closest relatives
to humans. They walk
on two feet longer than
any other apes feet.
Some bonobos in
captivity have learnt to
speak a human
language. Unlike other
apes, a bonobo society
is controlled by a
female. Today, bonobos
are found only in the
forests of central Congo
in Africa. There are so
few of them that they
are in danger of
becoming extinct.
44
Q Which is the largest of all apes?
A Gorillas are the largest apes. Adult males
are about 1.8 metres (6 feet) tall and weigh
up to 170 kilograms (375 pounds). They have
huge heads, a bulging forehead and a crest
with thick muscles on top of the head.
Although they are portrayed as aggressive and
dangerous killers, gorillas are in reality shy,
peaceful vegetarians. They are extremely
intelligent and can learn complex tasks. Each
evening, gorillas make nests using leaves and
twigs in which they curl up and sleep.
Gentle giant
Gorillas do not attack
anyone unless
provoked.
In danger
The siamang is distinct for two reasons.
First, two fingers on each hand are fused
together. The second is the large throat
pouch found among the males. The male
siamang can inflate this pouch to make
loud calls. The siamang is under serious
threat as forests are being cut down.
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Apes
Q Where can you find orangutans?
A Orangutans are the largest Asian apes,
found in the islands of Sumatra and Borneo.
The word orangutan means ‘man of the
forest’ in the Malay language. They have
large, bulky bodies, thick necks and long
arms. They move by swinging from one
branch to another. But because they are so
heavy, they frequently have to climb down and
walk on their four limbs. Orangutans are
omnivores, which means they eat both meat
and plants. They are extremely intelligent and
often use objects as tools, such as the big,
broad leaves that they use as umbrellas.
Unfortunately, despite being officially
protected, they are in danger of extinction
because of deforestation and hunting.
People of the forest
Orangutans are so close
to humans that they
can imitate many
of our actions.
Try these too…
Monkeys (42–43),
Other Prehistoric
Animals (94–95),
Africa (118–119), Asia
(120–121), Ancient India
and China (126–127),
Discovery of New Lands
(144–145), The Industrial
Revolution (148-149)
Q Why are gibbons known as lesser apes?
A Gibbons are smaller than the other
Q What is brachiation?
A Brachiation is a method by which gibbons
apes. They live in pairs rather than large
groups. They do not make nests and from
a distance they look more like monkeys than
apes. But their skulls and teeth are more like
those of the great apes.
and spider monkeys move about. In this type
of movement, they swing through tree
branches with their arms. They can swing
distances of about 15 metres (50 feet) at
speeds of 56 kilometres (35 miles) per hour.
Long hands
Gibbons are lesser apes
found in China, India and
parts of Southeast Asia.
These apes can swing
across large distances
from one branch to the
other using their long
arms. Gibbons can also
leap across distances of
up to 8 metres (27 feet).
Fatal bushmeat
Many species of
apes are killed
for their meat.
The meat of
these wild
animals is known
as bushmeat.
In some parts
of Africa,
chimpanzees in
particular are
hunted for food,
though this is illegal in most countries. Apes can also be carriers
of HIV, the virus that causes AIDS. Ape hunters often come into
contact with the infected blood, and this is one of the ways that
humans are suspected to have contracted AIDS.
45
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The Living Planet
Big cats
A big cat is a cat that can roar! This group includes the lion,
tiger, jaguar and leopard. They have large eyes, sharp teeth,
excellent hearing and powerful limbs with sharp claws. Most
have long tails and coats that are either striped or spotted. Big
cats are found in all continents except Australia and Antarctica.
Quick Q’s:
1. What do cats use
their tongues for?
A cat’s tongue is rough
and covered with
sharp, hook-like
projections called
papillae. Cats use their
tongues to clean the
flesh from the bones of
their prey and to
groom themselves.
2. How does a jaguar
kill its prey?
Q
How are big cats different from
other cats?
A Big cats are similar to our pet cats in
Hidden weapons
Big cats usually draw their claws into the paw (left)
and extend the claws (right) when about to jump
on their prey.
Q
What is special about the claws of a
big cat?
3. Are white tigers
albinos?
46
cannot roar, but purrs like our domestic cat.
However, it has many other characteristics of
a big cat, and is sometimes regarded as the
smallest member of the big cat family. It is
the fastest of all land animals, and can run
at a speed of up to 110 kilometres per hour
(70 miles per hour) over a short distance.
many ways. However, only big cats can roar.
This is because of a difference in the
structure of a bone that is present in the
mouth of all cats. This bone, called the hyoid
bone, connects the tongue to the roof of the
mouth. In small cats, the hyoid is hard, while
in big cats the hyoid is flexible, helping them
open their mouths really wide and roar aloud.
The jaguar uses its
powerful jaws and
sharp teeth to pierce
the skull of its prey
between the ears.
Its strong teeth can
even break open
turtle shells.
White tigers are not
albinos. A true albino
would not have stripes,
but white tigers have
prominent stripes.
They are not a separate
species, but differentlycoloured members of
the same species. Their
colour is caused by a
mutation in their
genes, which rarely
occurs naturally. In
recent times, the first
pair of white tigers was
found in a forest in
central India. Since
then, most white tigers
we know of have been
bred in captivity and so
can usually be seen
only in zoos.
Q Is the cheetah a big cat?
A The cheetah is not actually a big cat as it
A All big cats – except the cheetah – have
Roaring apparatus
The flexible hyoid bone of the big cats allows them to roar.
Living in a pride
Lions are the only big cats that live in prides. Each pride
has one adult male with three or four lionesses and their
cubs. Male cubs are thrown out of the pride as soon as
they become semi-adults.
retractable claws. These claws can be drawn
into the paw when the cat is not using them.
This prevents the cat from getting hurt while
grooming. The cheetah has short claws. It
uses them to get a good grip on the ground
while chasing its prey at high speeds.
Q
Why do the eyes of a big cat glow in
the night?
A The eyes of a big cat – or any other cat,
for that matter – have a mirror-like tissue in
them that gather even the faintest light and
focus it on an object, making it clearly visible
to the cat. It is this mirror-like structure that
causes the cat’s eyes to glow in the dark.
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Big cats
Q Are black panthers also big cats?
A Black panthers are actually black
leopards or jaguars. They are the result of a
condition called melanism that is common
among jaguars and leopards. This is when the
black pigment called melanin in the root of
the fur is produced in large quantities. It is
this condition that gives black panthers their
colour. A few leopards and jaguars have less
melanin than average. This gives them a
greyish colour, and they are often known as
white leopards or white jaguars.
Q Are teeth important to big cats?
A Big cats rely on their teeth to kill prey.
They have strong jaws, with three pairs of
incisor teeth, one pair of canines, two or
three pairs of premolars, and one pair of
molars. Apart from jaguars, all the other big
cats drive their large powerful canines into
the neck of their prey, between the gaps in
the backbone. The teeth cut through the
spinal cord, often killing the prey instantly.
The small but sharp incisor teeth located
between the canines help the cat scrape
meat off the bones. The molars help to
crack the bones open when the cat is feeding.
Jaguars usually attack their prey on top of
the skull, piercing it in between the ears.
They can do this because they have wider jaws
than those of other big cats.
Black panthers
Black panthers are actually
leopards or jaguars with
more than the usual amount
of melanin.
Q
How do big cats mark
their territory?
A All big cats are highly
territorial – each individual has
a particular territory that
includes hunting grounds, dens
and water holes. Big cats do not like
to share their territories, even with
members of their own species. They
warn other cats off by marking these
territories, usually by spraying urine or
scratching trees. Sometimes, big cats rub
their cheeks against rocks, trees or any
other object. Other cats usually leave the
area once they smell or see the signs.
Try these too…
Other Prehistoric
Animals (94–95), South
America (112–113),
Europe (116–117),
Africa (118–119),
Asia (120-121)
Solitary hunter
Adult leopards usually live
by themselves except
during the mating season.
But they require a smaller
territory than a tiger or
a pride of lions.
Mixing breeds
A ‘liger’ is born to a male lion and a female
tiger. This hybrid big cat looks like a lion
with stripes. Some ligers have manes, while
all ligers love to swim – just like tigers.
Ligers can grow to be giants. Some of
them even reach a height of about 4 metres
(12 feet) and weigh over 400 kilograms
(900 pounds). ‘Tigons’, which are born
to a male tiger and a lioness,
do not grow as big.
47
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The Living Planet
Bears
Bears can be found in a wide range of habitats, including
mountains and Arctic regions. There are eight species of bear –
the spectacled bear, the sun bear, the giant panda, the Asiatic
black bear, the American black bear, the brown bear, the sloth
bear and the polar bear.
Quick Q’s:
1. How do you know
when a bear is angry?
When threatened or
agitated, bears stand
up on their hind legs.
They probably do this
to appear larger to
their enemies. They
also use their clawed
paws to slash at
an attacker.
2. How does the giant
panda spend most of
its day?
The giant panda bear
eats about 18 kilograms
(40 pounds) of
bamboo leaves and
stems or about 40
kilograms (85 pounds)
of bamboo shoots each
day. It spends up to
14 hours just eating.
3. What is special about
the Kermode bear?
The Kermode bear is a
type of American black
bear. It inhabits the
rainforests of British
Columbia, Canada.
The Kermode bear is
the only black bear to
have a white coat.
4. Which is the smallest
bear in the world?
Sun bears are the
smallest of all bear
species. Even so,
they grow up to 1.5
metres (5 feet) in
length and weigh up
to 66 kilograms
(146 pounds).
48
Great swimmers
Polar bears are
excellent swimmers
and spend almost
as much time in
water as they
do on land.
Q
Do the eight species of bear
have any common features?
A All species are fairly
similar, although there
are slight differences in
size and diet. Bears have
stocky bodies, powerful limbs,
thick fur and a short tail. They
have elongated heads, rounded ears
and long snouts. They have a keen
sense of hearing and smell.
All bears, except the polar bear,
are omnivorous. Their varied diet
includes roots, nuts, fruit, berries,
honey, caterpillars and ants. Bear
teeth are small, and are mainly
used for defence or as tools. The
molar teeth are broad and flat,
suitable for shredding and
grinding fruit, nuts and berries.
Q Do bears have claws like cats?
A Bears have four limbs with
paws. Each paw has five long,
sharp claws. Unlike cats, bears
cannot retract their claws. They
use them to climb trees, open
termite nests and beehives, dig for roots,
and catch prey. All bears have long,
shaggy fur. The colour of
fur varies from
species to species.
Sharp claws
Bears have pads on their
feet to help them walk
and sharp, curved claws.
Ferocious grizzly
The brown bear, known as the grizzly bear in
North America, is a ferocious predator. When
threatened or during a fight for a mate,
grizzlies stand up on their hind legs and
use their long-clawed forepaws to fight.
Q Which is the largest of all
bear species?
A The polar bear is not only the
largest of all bears, but also the largest
carnivore on land. Found in the Arctic
regions, polar bears can grow to a
length of 2 metres (7 feet) and can
weigh up to a massive 800 kilograms
(1,760 pounds). They have creamy white fur
that blends in with the ice. Polar bears are
excellent swimmers and move quickly on land
and in water. They prefer to eat meat, and
their diet mainly consists of seals and young
walruses. During the summer when ice floes
(sheets of ice) melt and food is scarce, polar
bears feed on berries and bird eggs.
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Bears
Q Where can you find black bears?
A There are two kinds of black bear
– Asiatic and American. The Asiatic
black bear inhabits the temperate
and subtropical forests of Asia,
while the American black bear
is native to North America. The
Asiatic black bear is also known
as the moon bear because of the
white, crescent-shaped mark on
its chest. Its coat is mostly black
in colour, although bears with
brown coats are not
uncommon. The American
black bear is the smallest
of all North American
bear species, but it
can still grow up to
1.8 metres (6 feet)
in length and weighs
about 40–300
kilograms (90–660
pounds). Most of
these bears have
a glossy black coat,
although some are
honey-coloured.
Moon bear
The Asiatic black bear
is common in many
parts of Asia, such as
Siberia and Japan. In
some places it has
been domesticated
and taught to do
tricks, though this
practice involves
cruelty to the bear
and is now illegal.
Q How do sloth bears eat?
A The sloth bear has a flexible
white snout that is very useful for
digging food out of the
ground. The sloth bear
uses its long claws to rip
open the nests of ants and
termites. It then uses its
snout and hairless lips to
form a kind of suction
tube that sucks in its prey.
Try these too…
North America
(110–111), South
America (112–113),
Europe (116–117), Asia
(120–121), The Poles –
The Arctic and Antarctica
(122–123)
Good climber
Bears climb well and can
judge which branches will
take their weight. They
often climb high to reach
a beehive that has their
favourite food, honey.
Bees cannot sting them
through their thick fur.
Sleeping the winter away
Some bears, like brown bears, black
bears and polar bears live in places that
have very cold winters. Since food is
scarce in the winter, these bears spend
the time sleeping in warm, cosy dens.
Pregnant bears usually give birth during
the winter in these dens. Before they go
into their winter sleep, bears fatten
themselves up during the summer and
autumn when food is readily available.
This winter sleep is not the same as
hibernation as the bear can easily wake
up. Also, a bear’s body temperature does
not drop as drastically during the winter
as that of hibernating animals.
49
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The Living Planet
Canines
The canine family includes dogs, wolves, foxes, coyotes, dingoes
and jackals. Though dogs were probably the first animals to be
domesticated by humans, wild canines can still be found in every
part of the world. Wolves and wild dogs live in large packs, while
the other canines are solitary or live in small groups.
Q What makes canines good hunters?
A All canines have a keen sense of hearing
Fierce hunters
Wild African hunting dogs
are feared by other
animals because they do
not give up the chase.
Quick Q’s:
1. Which is the fastest
canine in the world?
Greyhounds are the
fastest canines in the
world. They have been
known to run at speeds
of up to 70 kilometres
per hour (44 miles per
hour). African hunting
dogs are also very fast
and can maintain
speeds of 50–60
kilometres per hour
(31–37 miles per hour)
for very long distances
while chasing prey.
2. What is unique
about fennecs?
Fennecs are the
smallest canines. These
tiny foxes are only 65
centimetres (2 feet)
long from the top of
their ears to the tips of
their tails, and weigh
less than 1.5 kilograms
(3.3 pounds). These
desert-dwellers have
huge ears that help
them to dispel excess
heat from their body.
50
and smell. As a result, they can locate prey
a long way off. Wild canines are very
determined hunters, willing to chase prey
over long distances. They also have several
sharp teeth used for killing, feeding and
defence. Canines use their chisel-like incisors
for cutting food and grooming. These are
located in the front of the mouth. Next to
them is a pair of dagger-shaped canine teeth
used for fighting and hunting.
Q Can canines run fast?
A Canines can run extremely fast and have
a lot of stamina. This ability is due to their
long legs and ankle bones. Canines have a
highly flexible backbone that can be arched
as they run. Their feet are small, and all their
toes have strong but blunt claws. Their small,
light feet and limbs help them to
run more efficiently than other
animals with larger
legs. Wolf packs and
hunting dogs are
known to chase their
prey for hours.
They finally
overtake
animals
that may
be faster
than them
over short
distances.
Q What is the structure of a wolf pack?
A Wolf packs have a breeding male, called
the alpha, which rules over the others in
the pack. He asserts his authority by using
dominant body posture, facial displays,
growls, barks, scent marking and at times,
even fighting. The alpha’s mate, called beta,
is the second in command.
Q Do foxes live in groups like wolves?
A Some species of fox, like the red fox,
live in small groups, but foxes usually hunt
alone. A male and female fox pair defends
the territory in which they hunt and raise
their young. Sometimes several female foxes,
usually a mother and her daughters, live in
a group with a single male. The younger
adults in a red fox group act as helpers,
assisting the breeding pair in defending
their territory and caring for the young.
Desert fox
Fennecs live in the hot Sahara desert. Their coats can
repel sunlight in the day and conserve heat at night.
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Canines
Wolf pack
Wolf packs are closely knit and usually all members are
related to one another, though distantly. The pack hunts
and feeds together, though smaller family groups may
sleep separately in dens that are close to one another.
Coyote legends
Coyotes are of very major cultural
significance to Native Americans. Most
Native American tribes have a character
called Coyote in their legends. According
to various stories, this character can be
a trickster or a hero. The coyote also
appears in creation myths of many tribes.
In fact, the Navajo tribe regards the
coyote as God’s dog.
Q How do canines hunt larger animals?
A Canine packs hunt larger animals
using a technique called relay hunting.
In this method, one member of the pack
chases the prey for a while, then another
takes over. Each member of the pack
takes a turn in chasing until the prey
becomes exhausted. The canines then
immediately surround the prey and
move in for the kill, often attacking from
behind and injuring their victim. In this
way, canines are able to take on very
large animals, such as bison.
Q Why do wolves howl?
A Howling is a popular method
of communication among wolves.
It helps pack members communicate
with each other, even when moving
through thick forests. Howling can
be used to gather pack members at
a specific location. It can also help
a wolf lay claim to its territory and
warn off rivals.
Howling wolf
There are many myths
surrounding the howling
of wolves. Wolves were
believed to howl at the
full moon. However, this
is because they are more
likely to hunt on a bright
night and they howl to
bring the pack together.
Try these too…
North America
(110–111), South
America (112–113),
Europe (116–117),
Africa (118–119), Asia
(120–121), Native
Americans (133–135)
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The Living Planet
Elephants
Elephants are the world’s largest land animals. They are divided
into three different species – savannah, forest and Asian
elephants. Savannah and forest elephants are together known
as African elephants.
Tragic tusks
Elephants have often
been hunted for their
precious ivory tusks.
Q
How do
elephants use their trunks?
Quick Q’s:
Q How are African elephants different
A The elephant’s trunk is a combination
1. Do the members of
a herd stick together?
from Asian elephants?
of its nose and upper lip. The elephant uses
its long, flexible trunk to grasp objects, pluck
leaves, break off branches and carry heavy
objects like logs. While strong, the trunk is
also very sensitive. Small, finger-like
projections at the end help elephants to pick
up small objects. The trunk is also used to
suck in water for drinking or to spray water
over the body for bathing. Elephants
pick up dust with their trunks in
the same way when they want to
have a dust bath. When lying in
water, the elephant sticks its trunk
out to breathe. Elephants use the
nostrils at the tip of the trunk to
capture the scent in the air.
The trunk is then placed in
their mouth, where special
organs identify the scent.
The members of a
herd feed, bathe and
migrate together. They
usually stay very close
to the leader. They also
protect one another
from predators. The
young, sick and old are
especially well-defended
by the healthier
members. When faced
with danger, the head of
the herd leads the rest
away. When the leader
dies, the next oldest
female takes over.
2. Do elephants eat
a lot?
The elephant’s
digestive system is very
weak. It can digest
only 40 per cent of the
food it eats. It has to
make up by eating a
great deal. An adult
eats about 140–270
kilograms (300–600
pounds) of leaves and
grass every day.
3. How big are the
tusks of an African
elephant?
An African elephant’s
tusks are between
1.8–2.4 metres (6–8 feet)
in length and weigh
about 20–45 kilograms
(50–100 pounds).
Those of an Asian
male are only about
1.5 metres (5 feet)
in length and weigh
about 30 kilograms
(70 pounds).
52
A
African elephants are larger and have
less hair. They have bigger, fan-shaped ears.
Both male and female African elephants have
tusks. In contrast, Asian elephants have lowerhanging ears and only the male members
have tusks. The savannah
elephant is light grey,
while forest and Asian
elephants have dark
grey skin.
Big pet
Asian elephants have
been domesticated by
people for centuries.
Q Are the elephant’s tusks really teeth?
A The tusks of an elephant are simply
elongated incisor teeth. A calf is born with a
pair of incisors that are replaced within 6 to
12 months. The second set grows into tusks.
Moving in a herd
A herd of African elephants moves towards a watering
hole. Note how the young members of the herd are
surrounded by older and stronger members for
protection. Elephant herds are led by the oldest female.
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Hoofed Animals
Hoofed Animals
Try these too…
The nails of some mammals are large and hard enough for them
to walk on. These nails are called hooves and such animals are
called hoofed animals, or ungulates. This group includes pigs,
hippopotamuses, camels, giraffes, goats and cattle.
Q How did the hippopotamus get its name?
A The word hippopotamus means river
Camel’s cousin
The llama is found in the
Andes mountains.
horse in Greek. The hippopotamus spends
a large part of its day in shallow water and
usually comes out only at night.
Q How are llamas different from camels?
A Llamas are found in South America.
Q Do hippopotamuses sweat blood?
A Common hippos do not have sweat
Although they are in the same family as
camels and even look a lot like them, llamas
do not have humps. They are usually white,
with black and brown patches. Alpacas are
similar to llamas but much smaller.
glands, but their pores secrete a reddish-pink
fluid which is often mistaken for blood. This
fluid gives their skin a shiny appearance and
prevents it from cracking in the heat.
North America
(110–111), South
America (112–113),
Africa (118–119), Asia
(120–121), Ancient
Americas (132)
Hollow weapon
Antelope horns are hollow
and light. But they are
still formidable weapons.
Q Is there any difference between antelope
and deer?
Q How many species of camels are there
A All species of antelope have pointed,
in the world?
hollow horns that are permanent. Deer have
branched antlers that they shed every year.
Deer antlers are solid and bony. Only male
deer grow antlers, while both male and
female antelope have horns.
A There are two species of camels. They
are the Bactrian and the Arabian camel. The
Bactrian camel has two humps on its back,
while the Arabian camel has one. The humps
contain fat that provides the animal with
nutrients when food is not available.
Two humps
The Bactrian camel (above) is found in the Gobi desert of
Mongolia. The Arabian camel is found in Asia and Africa.
Living tall
The giraffe is the tallest living mammal.
An adult male giraffe can grow to a height
of about 6 metres (20 feet). In contrast, the
giraffe’s body is not as long as that of most
other hoofed animals. Its front legs are
slightly longer than its hind legs. Giraffes’
necks can be over 1.5 metres (5 feet) in
length, but only have seven vertebrae (neck
bones). Its long neck and extraordinary
height help the giraffe to pluck leaves that are
beyond the reach of other animals. Giraffes
also have tongues that can be extended as far
as 45 centimetres (18 inches)!
53
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The Living Planet
Odd-toed Mammals
Some mammals have an odd number of toes or hooves. This
group includes animals like horses, zebras, rhinoceros and
tapirs. Horses, zebras and donkeys have only one toe in each
foot, which is in the form of a hoof. A rhinoceros has three toes.
Tapirs have four toes in their front feet, three in their hind feet.
Q
Does the tapir belong to the same family
as zebras and rhinos?
A Although it looks a lot like a pig, the
tapir is in fact closely related to zebras and
rhinos. This animal has a short, muscular
trunk and is about 1 metre (3.2 feet) tall.
It has splayed hooves, which help it to get
a firm grip on soft, muddy ground.
Staying in a herd
Plains zebras are among
the most common animals
seen in the African
savannah. They usually
do not go very far
from watering holes.
Quick Q’s:
Q How can you tell the different types of
1. Where did the horse
come from?
zebra apart?
The earliest ancestor of
the horse lived in
North America about
55 million years ago.
It was the size of
a small dog, and did
not look anything like
today’s horse. But its
teeth were like any
horse we know today.
This animal went
through many changes
over millions of years
before the modern
horse evolved.
2. Where are tapirs
found?
There are five species
of tapirs in the world.
Three of these are
found in the
rainforests of South
America, while the
other two inhabit parts
of southeast Asia and
Iran. All tapirs prefer
water to land and
spend a great deal of
time in lakes and
streams.
54
Mother and child
Baby tapirs are various
shades of pink and have
prominent stripes. Their
colour changes to grey
and white and the stripes
fade as they grow older.
A
There are three main kinds of zebra –
the plains, mountain and Grevy’s zebra. The
plains zebra, found in the African grasslands,
is the most common of all three species. It is
striped all over and its stripes are wider than
those of the other two species. Mountain
zebras are native to the mountainous regions
of southwest Africa. They have a white belly.
Grevy’s zebra is the largest of the zebra
species. It has a mane that stands up straight,
large ears and narrow, closely set stripes that
extend all the way down to its hooves.
Q How many species of rhinoceros are there?
A There are five species of rhinoceros in
the world today. They are the Sumatran,
Javan, Indian, white and black rhinoceros.
The white and black rhinoceros are found in
Africa, while the others live in Asia. All rhinos
have thick skin with folds. They have short,
thick legs and a tiny tail. They are solitary
animals that come together only during the
mating season.
Under threat
Indian rhinos have one horn, while African rhinos have
two. The horns are supposed to have healing properties
and are used in various forms of traditional medicine.
As a result, rhinos have been hunted and now their
numbers have grown alarmingly small. There are so few
Javan and Sumatran rhinos left that the species is under
threat of extinction.
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Odd Mammals
Odd Mammals
Most mammals share certain characteristics. The majority
of mammals give birth to live young and look after them,
and most of them (apart from some sea mammals)
have four limbs and live on land. But there are some
exceptions, such as platypuses, anteaters and bats.
Q Do any mammals lay eggs?
A The duck-billed platypus and the spiny
anteater lay eggs. They are found in Australia,
Tasmania and New Guinea. They were among
the first mammals on Earth. Apart from
laying eggs, they are similar to other
mammals. They are warm-blooded, have hair
and produce milk to feed their young. But
neither anteaters nor platypuses have any
teeth. They have snouts that look like beaks.
Q Why do some mammals like kangaroos
carry their babies in a pouch on their bellies?
A Kangaroo babies are born early, before
It’s a
mammal
The platypus lives
in and around rivers
in eastern Australia
and Tasmania. The male
has a spur on the hind
foot that can secrete poison.
Following its echo
Bats use a special sense of vibration, called
echolocation, to find food and to navigate.
They emit sounds that bounce back as echoes after
striking an object. Bats can identify the direction,
distance, speed, and sometimes, even the size of an
object by listening to this echo.
This special technique helps them to find food
and avoid obstacles in the dark.
they have finished developing. When the baby
is born, it climbs into its mother’s pouch
where it remains for several weeks until it
is strong enough to move about on its own.
The baby may remain in the pouch for more
than a year, climbing out to play more and
more often. Apart from kangaroos, koalas,
possum and wombats also carry their
babies in a pouch. All the mammals that
do this are known as marsupials.
Q How are bats able to fly?
A The front legs of bats act as wings. Each
leg has four long fingers to support the wing.
The wings have a double layer of skin
stretched between the finger bones and
attached to the side of the body and to the
hind legs. Bats have three pairs of flight
muscles, attached to the upper arms and
chest, that give them the power to fly.
Big jumper
The kangaroo can jump
so far that it is difficult
to catch one. Their
numbers have grown
many times in the absence
of predators in Australia,
where they live.
Try these too…
South America
(112–113), Australia
and Oceania (114–115),
Europe (116–117),
Africa (118–119),
Asia (120–121)
55
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The Living Planet
Whales
Whales might live in the oceans and might even look like very
large fish, but they are mammals. Like most other mammals,
whales give birth to live young and breathe with their lungs.
Whales belong to a group of animals called marine mammals.
They are among the largest animals on the planet.
Quick Q’s:
1. What is blubber?
Blubber is a layer of
fat found between the
skin and flesh of all
whales. It preserves
body heat and stores
energy as well as
keeping whales afloat.
2. Do whales live as
a family?
Q Why do whales have holes on their heads?
A Whales do not have gills like fish. Instead
they take in air through nostrils like all the
other mammals. The nostrils of whales, called
blowholes, are located on top of their heads.
Every once in a while, whales come to the
surface of the water and open their blowholes
to breathe.
A The whale opens its
blowhole to breathe out stale
air. When this air
comes in contact
with the colder
air outside, the
water vapour in
the atmosphere
condenses. This
looks like a
fountain or
spout.
3. What do whales use
their tails for?
The tail of a whale is
divided into two parts,
called flukes. While
fish move their tails
sideways to swim,
whales swim by moving
their flukes up and
down in the water.
4. Which is the largest
whale in the world?
56
Q Is that a fountain of water coming
out of the blowhole?
Most whales are social
creatures. They travel
and feed in groups
called pods. Many of
them migrate long
distances in groups
between their feeding
and breeding grounds.
Blue whales are not
only the largest whales,
but also the largest
animals ever to live on
Earth. They can be as
long as 34 metres (112
feet). They are also the
loudest animals on
Earth – 1.5 times as
loud as a pneumatic
drill. But they use such
a low frequency that we
cannot hear them.
There she blows
Whale hunters and whale watchers spot whales by the
fountain of water coming out of their blowholes.
Killer whale
The killer whale or orca is the most common member of
the family of marine mammals that includes whales and
dolphins. They can be found in all the oceans of the
world. They are highly social animals and travel in stable
groups, led by the oldest female member of the group.
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Whales
The baleen comb
A humpback whale
and its comb of
baleen (inset).
There was a
time when
baleen was
used in
women’s
clothing, and
many whales
were hunted
for it.
Long way home
Every year the California grey whales migrate for about 20,000
kilometres (12,427 miles). They migrate all the way from the
Arctic Ocean to the Mexican coast and back. This is the longest
migration undertaken by any mammal. In total, the California
grey whale spends about one-third of its life migrating.
Q Do whales like to play?
A Although they are very big, whales can
Q Are whales vegetarian?
A Whales are divided into two main groups
– toothed whales who hunt for prey and
baleen whales, who feed on krill, plankton
and other tiny marine creatures in the water.
Toothed whales, including killer whales,
sperm whales and beluga whales, have small,
sharp teeth in their jaws. These teeth are used
to kill prey. Baleen whales, including grey
whales, humpback whales, bowhead whales
and blue whales, are toothless. Instead, they
have sieve-like structures, called baleen, that
hang from their upper jaws. The whales swim
with their mouths open, taking in lots of
water rich in tiny animals such as krill and
plankton. The prey gets trapped in the comblike edges of the baleen plates and the whale
licks the food off the plate.
be playful. Sometimes they pop their heads
above the surface and float motionless. This
behaviour is known as ‘logging’. Some whales,
like humpback whales and orcas, leap right out
of the water, which is known as ‘breaching’.
Whales also stick their tails out and splash
them around. This is called ‘lob-tailing’.
Try these too…
Oceans (34–35), Other
Marine Mammals
(58–59), Origin of Life
(88–89), North America
(110–111), Australia and
Oceania (114–115), The
Poles – The Arctic and
Antarctica (122–123),
Native Americans
(133–135), Discovery of
New Lands (144–145)
The giant
Only a small part of this
blue whale is seen above
the surface of the ocean.
Unlike other baleen
whales, blue whales do
not live in large groups.
These huge animals need a
lot of space in which they
can get enough food to
support themselves. In
autumn, which is the
mating season, they can
sometimes be seen in
pairs. Female blue whales
give birth once every two
or three years.
57
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The Living Planet
Other Marine Mammals
Seals, walruses and sea lions fall in the group of ‘fin-footed’
mammals who can move across land using their fins. All species
in this group take to the water almost every day, and get their
food underwater. There are 18 species of seals today, making
them the largest group of fin-footed mammals.
Quick Q’s:
1. Which seal dives
the deepest?
Weddell seals are not
only good swimmers,
but also great divers.
They have been known
to dive to depths of
over 500 metres (1,600
feet), and stay there for
more than an hour.
Q Why are seals good swimmers?
A Seals have a torpedo-shaped body that
makes it easy to move through water. They
also have strong limbs shaped like paddles
that help to propel them forward.
Large colony
Seals live in large colonies on remote islands.
The colonies are divided into nurseries, an area for
half-grown seals, and an area for adult seals, which is
nearest to the sea.
2. Which are the largest
and smallest seals in
the world?
Seals range in size from
1 metre (3 feet) to
over 5 metres (16 feet).
Galapagos fur seals
and ringed seals are
the smallest, while
the male southern
elephant seal is the
largest in the world.
3. Why was the sea
otter hunted so
extensively?
The sea otter has the
densest and most
luxurious fur among all
mammals. The brown
fur has up to 394,000
hairs per square
centimetre! This fur was
sought after by the
richest people in the
eighteenth and
nineteenth centuries.
So the sea otter was
hunted all over the
North Pacific, until it
was almost extinct. The
animal has been
protected from hunters
in recent decades and it
is showing signs of
recovery.
58
Q Why do seals appear clumsy while
walking on land?
A
Most seals are very clumsy on land.
Their front limbs are of no use for walking,
and they slide on ice with great difficulty.
Some types of seals have longer, more mobile
flippers, so they are better adapted for
moving on land. When on land, seals are
most vulnerable to hunters.
Sleek predator
A seal becomes a sleek, fast predator the moment it is in
water. Most seal species are able to stay submerged and
chase their prey for many minutes without breathing.
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Other Marine Mammals
Fast asleep
Walruses can be found sleeping on rocky beaches most
of the time. Occasionally, one of them will slip into the
water, hunt for a while, then return to the beach and
go to sleep once more.
Q How are walruses different from seals?
A Walruses are much bigger than seals.
They inhabit the Arctic regions at the edge
of the polar ice sheet. The most unique
feature of the walrus is its tusks, which are
actually a pair of elongated upper canine
teeth. Walruses use these tusks not only to
defend themselves, but also as hooks to climb
out of the water on to the ice. Male walruses
have bigger tusks, which they use during
courtship fights. Like all marine mammals,
walruses have a layer of blubber that protects
them from the cold.
The siren
Dugongs and manatees are the sirens of Greek
mythology. Ancient sailors probably mistook these
animals for creatures that were half-fish and halfhuman, giving rise to the legends of beautiful
half-women-half-fish who lured sailors to their death.
In reality, however, dugongs and manatees are very
different from the sirens of legends. They are heavy
animals, like a huge, thick sausage, tapering a bit
towards the tail. They swim slowly near the shore,
eating sea grass and other underwater vegetation. They
are better described by their other name – sea cows.
Q What do sea lions eat?
A Sea lions are the largest member
of the eared seal family. An average male
Steller’s sea lion weighs 907 kilograms
(2,000 pounds). These animals eat only small
fish, squids and octopus most of the time,
though they have been known to prey on
other seal species from time to time.
Star performer
Sea lions are highly
intelligent. They are
popular at aquarium
shows, where they catch
and throw balls with ease.
Try these too…
Whales (56–57), North
America (110–111),
South America
(112–113), Australia and
Oceania (114–115), The
Poles – The Arctic and
Antarctica (122–123)
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The Living Planet
Seabirds
Birds that spend most of their time at sea are called seabirds.
These include skuas, gulls, terns, auks, penguins, pelicans,
petrels, gannets and cormorants. The earliest seabirds had teeth
and lived in the Cretaceous period, which began 146 million
years ago. Modern seabirds have been around since the
Palaeogene period that began 65 million years ago.
Quick Q’s:
1. Are most
seabirds white?
Seabirds are white,
grey or black. These
colours help them
hide from enemies
and also from prey.
Their legs and beaks
are sometimes
brightly coloured.
2. How do seabirds
catch their food?
The albatross feeds on
fish and krill that are
found on the surface
of the water. Gannets
and boobies dive to
pick up prey. Some,
like the chinstrap
penguin, dive and
chase their prey.
Skuas and frigate
birds are known to
steal food from others.
Q Do seabirds ever live on land?
A Seabirds come on to land to lay their
eggs. The snow petrel nests 483 kilometres
(300 miles) away from the sea on the Antarctic
continent. Although seabirds usually fly and
fish alone, most of them nest in colonies on
land. The colonies house anything from a few
dozen to more than a million
birds. Murres build their
nests close to each other
for protection, while
albatrosses prefer to
leave space between
their nests.
Good divers
Murres dive beneath the
surface to feed on fish.
Q How are seabirds different from other
kinds of birds?
3. Is so much salt good
for birds?
Seabirds have salt
glands on their face that
excrete some of the salt
they take in. But the salt
does not seem to harm
the birds – seabirds live
longer than other types
of birds. In fact, the
albatross can live
for up to 60 years.
A
Seabirds have adapted to life around
saltwater. Birds like the albatross that fly
long distances over the open ocean have
long, strong wings to help them glide, while
birds that dive for fish have shorter wings. All
seabirds have webbed feet so that they can
skim the water’s surface or dive down in to
the water with ease. Seabirds have lots of
feathers that are packed densely, to keep
out the water. A thick layer of down
keeps them warm.
Strange nest
Petrels make their nests
with pebbles. They move
to land only to breed.
60
Good dads
Unlike most birds, the
male phalarope guards
his eggs until they hatch.
Drying up
After fishing, cormorants have to spread out their wings
to dry as they do not have waterproof feathers.
Q How far does a seabird migrate?
A Seabirds migrate a long way to lay eggs.
The Arctic tern holds the record for flying
longer distances than any other bird. When it
is summer in the northern hemisphere, it
flies up to the Arctic. And when
it is summer in the southern
hemisphere, it flies all the way
to Antarctica. The terns travel
20,000 kilometres (12,000
miles) each way! Other long
distance flyers include
sooty shearwaters,
albatrosses and
phalaropes. While many
seabirds fly over the open
sea, many are happy to
keep close to the shore.
Q What kind of parents do seabirds make?
A Seabirds make good parents. They nest
at safe spots and are careful with their eggs.
Both the mother and father care for their
young. Some seabirds care for their young for
six months, while some, like frigate birds,
watch their young for fourteen months.
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Birds of Prey
Birds of Prey
Birds
of prey
(raptors)
are meat-eating
birds that use their
beaks and claws to hunt.
There are about 500 species of birds of
prey. The largest of them is the male Andean
condor, and the elf owl is the smallest.
large, forward-facing eyes
soft, round wing edges
for slow flying
Night vision
Owls can see and hear
well at night.
Q Which birds are raptors?
A Vultures, hawks, eagles, kites, falcons,
Q Do birds of prey have special wings?
A Falcons have thin, pointed wings. These
harriers, buzzards, owls, secretary birds and
ospreys are all types of birds of prey. Of these,
only owls hunt at night. Female raptors that
feed on live prey are often larger than the
males, although male and female vultures are
the same size. Vultures feed on carrion, or
dead animals, instead of live prey.
help them to fly fast, and to change their
direction while chasing their prey. Their wings
also enable the falcons to dive suddenly to
catch their prey. Hawks and eagles have
rounded wings that help them soar, without
flapping their wings, high up on air currents.
They are able to mark their prey even from
high up in the air.
Majestic birds
Eagles are larger than
most other raptors,
and they are more
powerfully built. Their
large pupils give them
good night vision.
Q What makes raptors such good hunters?
Q What do raptors eat?
A Raptors have larger eyes than most other
A All raptors are meat-eaters. Some, like
birds and have excellent colour vision. They
have a sharp, curved beak and strong feet
with powerful claws (talons). Raptors’ sharp
ears can hear prey moving and detect how
far away it is.
That’s really high!
Did you know that a Ruppell’s griffon
vulture can fly as high as 11,000 metres
(37,000 feet)? On 29 November 1973,
one of these birds crashed into an
aircraft over the Ivory Coast!
eagles, feed on rodents, snakes, lizards and
fish. Most vultures feed on carrion. Vultures
have a sensitive sense of taste, so they are able
to detect if food is poisonous. Some vultures,
like the palm nut vulture, eat the fruit and
husks of certain palm trees as well as shellfish
and carrion. Bat hawks, unsurprisingly, exist
on a diet of bats.
Q What is a raptor’s gizzard?
A A gizzard is a specially adapted stomach
that helps a bird to grind food. Birds often
have stones inside their gizzards. Birds of prey
have a special gizzard, which makes pellets
out of whatever the bird cannot digest, like
hair, bones and feathers. When it has finished
eating, the bird spits the pellets out.
Bald and beautiful
Vultures do not have
feathers on their heads
and necks. This ensures
that they do not get too
dirty when they stick
their heads into carcasses,
which helps to prevent
infection.
Try these too…
North America (110111), South America
(112-113), Africa (118119), Asia (120-121),
The Poles – The Arctic
and Antarctica (122-123)
61
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The Living Planet
Songbirds
The crow and the nightingale have something in common — they
are both songbirds. There are about 4,500 species of songbirds.
These include crows, finches, larks, mockingbirds, nightingales,
ravens, robins, sparrows, thrushes, weaverbirds and warblers.
Quick Q’s:
1. When did the first
songbirds sing?
The first songbirds
appeared about 50
million years ago. They
were found in the
lands now known as
Australia, New Zealand
and Antarctica in the
southern hemisphere.
2. Which is the
largest songbird?
The raven, which is
part of the crow family,
is the largest songbird,
measuring about
60 centimetres
(24 inches) in length.
All members of the
crow family are
songbirds, though it
may not seem so to us.
3. Do songbirds only
live on land?
Most songbirds are
found on land. The
five species of dipper
are the only aquatic
songbirds.
Q What makes songbirds special?
A Songbirds have specially developed
vocal cords (syringes) which they use to
produce sounds or ‘songs’. Some songbirds,
like the wood thrush, can control both
syringes independently and therefore sing
two songs at the same time. Unlike other
birds, songbirds have a special section
in their brains that helps them to learn
their songs.
Q Why do songbirds sing?
A Most male songbirds sing to catch
the attention of a female songbird.
Female songbirds are attracted to
males that are good singers. So,
males try to sing loud and for as
long as they can.
Q
Do songbirds have to learn
from their parents how to sing?
Tree life
Most songbirds have
toes arranged in a way that
helps them to perch on trees.
Q How long do songbirds usually live?
A Songbirds live for about five years. They
lay their first clutch of eggs when they are less
than one year old. The eggs often hatch after
just ten days. The hatchlings are born blind
and have no feathers. In contrast, the egg of
an albatross, which is not a songbird, takes
80 days to hatch, so the hatchlings are much
more developed.
A Scientists have found that a young
songbird that has not learnt to sing from its
parents can only sing a short song. Songbirds
learn their songs when they are very young,
by listening to their parents.
Q Where do songbirds live?
A Most songbirds live in trees and often
Wood thrush
The wood thrush sings a
melodious flute-like song.
62
feed on fruit, berries and insects. In most
places, you just have to look out of the
window to find a songbird – eight out of
every ten perching birds are songbirds!
Copy cat
Starlings are strange birds. They copy the songs of other
songbirds when they run out of their own songs.
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Waterfowl
Waterfowl
The waterfowl family is made up of ducks, geese and swans.
Waterfowl can swim, float and even dive. Many waterfowl migrate
long distances every year.
Q
How have waterfowl adapted to life
in the water?
A Waterfowl have webbed feet that help
them paddle. They have flat bills, and their
feathers have a coating of oil that works like
waterproofing. The feathers of ducks, eider
(sea ducks) and geese are soft and warm.
They are used to stuff pillows, quilts and
sleeping bags.
Q What makes a goose a goose?
A Geese live in the northern hemisphere.
They are long-necked migratory birds that
love the water. The Canada goose is the
biggest goose in the world, while the rare
lesser white-fronted goose is the smallest
goose in the world. The Abyssinian bluewinged gander (male goose) tries very hard
to win the female’s attention. It struts around
with its head bent over its back, showing off
its blue wing patch. The nene, the official
bird of Hawaii, is a land goose.
Is that a quack?
Different waterfowl have different calls.
Female mallards honk loudly, but the
male mallard’s sound is softer. The
tundra whistling swan has a sharp whistle
that can be heard up to 6 kilometres
(3.7 miles) away. Geese make a sound
like a ‘honk’, while ducks quack.
Grace in feathers
Black swans are found
in Australia. They are
excellent swimmers. They
are also the fastest flyers
among waterfowl.
Q Why do waterfowl migrate?
A Most waterfowl are migratory. They
migrate to avoid the heavy rains and
hot summers in the south and the bitter
winters in the north. Waterfowl often travel
long distances in search of pleasant weather.
Snow geese nest in the Arctic tundra in the
summer and fly south to spend the winter in
Mexico. In winter, bar-headed geese migrate
from India to Tibet. They fly 1,600 kilometres
(1,000 miles) a day over the Himalayas, the
highest mountains in the world. Flying at
3,600–4,300 metres (12,000–14,000 feet), they
survive winds that blow at more than 322
kilometres per hour (200 miles per hour)
and freezing temperatures. Although oxygen
is low at such heights, waterfowl are able
to absorb more oxygen with each breath
while flying.
Try these too…
Oceans (34–35),
North America
(110–111), South
America (112–113),
Africa (118–119),
Asia (120–121)
Big goose
The Canada goose
has a wide wingspan of
160 centimetres (5 feet).
Q What makes ducks different from
other waterfowl?
A
Ducks are smaller than swans and geese.
They have squat bodies, and are found in
both freshwater and saltwater. They have big,
flat bills that help them to scoop food off the
water’s surface or from just below it. Small,
freshwater ducks are called teals. Another
group of ducks, called wigeons, have lovely
blue-grey bills. Dabblers are ducks that stand
and fish in shallow water. The eider is a large
sea duck prized for its soft feathers. Most of
the common domestic ducks are mallards.
Tough customer
Geese can be very
aggressive if they
feel threatened.
63
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The Living Planet
Flightless Birds
Not all birds can fly. Some, like the ostrich and penguin, have
such short, weak wings that they just cannot take to the air.
Most flightless birds are believed to have occupied islands
where there were no predators. In the absence of real danger,
these birds did not really need to fly.
Kiwi
The kiwi is a small,
shy, nocturnal bird.
It has nostrils at the
end of its long bill and
a keen sense of smell.
The kiwi is the
national symbol
of New Zealand.
Q Where are flightless birds found?
Q How do flightless birds defend
themselves from predators?
A Most flightless birds are found on small
A Many flightless birds became extinct
islands. New Zealand has the largest number
Kakapo
The kakapo’s green colour
helps it blend in with its
leafy surroundings.
Quick Q’s:
1. Which is the smallest
flightless bird?
The Inaccessible Island
rail, of the South
Atlantic is the world’s
smallest flightless bird.
It is no more than 17
centimetres (7 inches)
and weighs less than
30 grams (1 ounce).
2. Was there ever a
flightless bird that was
larger than the ostrich?
The aepyornis that
lived on the island
of Madagascar was
the largest bird ever
to live on this planet.
It was more than
3 metres (10 feet)
tall and weighed
about 500 kilograms
(1,100 pounds).
3. What do kiwis use
their beaks for?
Kiwis have nostrils
at the end of their
long beaks. They
thrust their beaks
into the ground in
search of food.
64
of flightless birds, from kiwis and penguins, to
the now extinct moa. This country is also
home to the kakapo – the world’s
only flightless parrot.
Q Why can’t flightless birds fly?
A All flying birds have a keel, or
breastbone, to which powerful muscles
that aid flying are attached. In flightless
birds this keel is either very small or
completely absent. This makes their
wings weak, so they cannot fly.
because of their inability to fly. However,
others have unique adaptations that
protect them from a similar fate. For
example, ostriches can outrun most of their
predators and can also deliver a fatal kick
with their clawed feet. Others, like penguins,
are excellent swimmers. Most flightless birds
have colours that help them blend in to
their surroundings.
long featherless neck
short tail
Q
Which is the world’s largest
flightless bird?
A The ostrich is not only the largest
flightless bird, but is also the biggest of all
living birds. It can grow to a height of
about 2.5 metres (8 feet) and can weigh up
to 150 kilograms (330 pounds). Ostriches
may not be able to fly, but they run at
speeds of about 65 kilometres per hour
(40 miles per hour).
Survival
The Inaccessible
Island rail has
survived because
there are few
predators where
it lives.
long legs
Danger, danger!
When in danger, the
ostrich lies flat on the
ground with its neck
stretched out. This
helps it to blend into
its surroundings.
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Penguins
Penguins
Penguins are the most common flightless birds. There are about
17 different kinds of penguin in the world, most of which are
found in the Antarctic region. Underwater, the wings of
penguins act like flippers, helping these birds to swim at
speeds of about 24 kilometres per hour (15 miles per hour).
Royal looks
The emperor penguins
look majestic with their
big heads, smart black
hoods and patches of
bright colour on their
bodies and faces.
Q Which is the world’s largest penguin?
A The emperor penguin is the tallest and
Q
How can penguins live in places as cold
as Antarctica?
A Like whales, penguins have a thick
layer of fat (blubber) that protects them
from freezing temperatures. Their feathers
are stiff and tightly packed together. A special
structure near penguins’ tails produces
oil that coats their feathers and makes
them waterproof.
Q Can penguins walk?
A Penguins are very clumsy on land. Their
the heaviest of all penguins. This species
can grow to a maximum height of about
1.1 metres (3.7 feet) and can weigh about
41 kilograms (90 pounds). The smallest
penguin is the fairy penguin which is barely
41 centimetres (16 inches) tall and weighs
about 1 kilogram (2.2 pounds).
Tough life
The Antarctic region
remains frozen most of
the year. Creatures living
here have a layer of
blubber and other
adaptations that help
them survive the cold.
Try these too…
The Poles – The Arctic
and Antarctica (122–123)
Model dad
Male emperor penguins make one of the best fathers in the
animal kingdom. After laying a single egg the female penguin
goes out to the sea in search of food. The male holds the egg
on his feet under a warm layer of skin called the ‘brood pouch’
to hatch it. The egg takes about 60 days to hatch, and the male
continues to guard the chick through the winter. He goes hungry
until the female returns.
feet are paddle-shaped and are better equipped
for swimming than walking. When on land,
penguins waddle about slowly. Sometimes they
even slide across the ice on their bellies.
Q What do penguins eat?
A Most penguins feed on krill, fish and
squid. They catch and swallow their prey
as they swim. Penguins can dive almost
500 metres (1,640 feet) in search of food.
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The Living Planet
Fish
Fish are cold-blooded vertebrates (animals with a backbone),
that live in water and mainly breathe through gills. Some, like
the lungfish, have lungs to breathe with. Most fish have scales
for protection and fins to help them swim. Fish were one of
the earliest creatures to inhabit the Earth. They appeared about
500 to 475 million years ago.
Quick Q’s:
1. Do fish look after
their eggs?
Most fish lay their
eggs and then swim
away. But not the
seahorse. Seahorses
make very caring
parents. The female
seahorse lays eggs in
a pouch on the male’s
stomach, and the male
then carries these eggs
for three weeks until
they hatch. The male
stickleback fish builds a
nest of algae and
other aquatic plants
for its eggs. It also
releases a sticky gluelike substance to hold
the nest together.
2. Do fish go to sleep?
Some fish enjoy a nap.
All members of the
parrotfish family sleep
at night. They make a
bed out of their own
saliva that covers them
fully. Then they go to
sleep on the sea floor.
But most other types
of fish continue to
swim slowly even
when they are resting,
so it’s difficult to tell if
they have gone
to sleep.
3. What are fins?
Fins are thin skin
stretched over fan-like
bones. A fish usually
has pectoral, dorsal
and caudal (tail) fins
that help it to swim.
66
Q What were the earliest fish like?
A The first fish were jawless and finless.
There is one such fish, the lamprey, that still
exists. It looks like an eel, with a mouth like a
sucker, sharp teeth and no fins. The hagfish is
another early fish that can still be seen today.
It lives in saltwater and feeds off the insides of
dead fish. It defends itself by secreting slime.
Today, most other fish have jaws and fins.
Q Do all fish have bones?
A Most fish do have bony skeletons. There
are two groups of bony fish – lobe-finned and
ray-finned fish. Their fins have different
shapes. Lobe-finned fish include lungfish and
the prehistoric coelacanth. Other commonly
known fish, including herring, tuna, salmon,
sunfish and flatfish, are ray-finned fish.
Q What about the boneless fish?
A Sharks, rays and skates are all fish that
have no bones at all. Their skeletons are
made of cartilage, which is a rubbery tissue
softer than bone. These fish have strong jaws
and sharp teeth. Their mouths are on the
lower part of their heads, while their eyes are
on top. This means they can’t see
dorsal fin
what they are eating.
eye
long blade like snout
mouth
Smart moves
Do you know how the
male seahorses win over
females? They display
their pouch, where they
will carry eggs. They open
and close the pouch and
even fill it with water to
show off. Male seahorses
also have tail pulling
competitions to impress
the females and also snap
at and wrestle with one
another.
pouch to
carry eggs
tail
Q How many species of fish
are there?
A
There are over
40,000 species of fish.
Most fish live either in
freshwater or in saltwater, but not both. Some
fish which live in the sea, like salmon, move
into rivers to breed. Some freshwater eels do
the opposite and breed in the sea.
Bones and all
This is a ray-finned fish.
Its fins are adapted for
swimming.
second
dorsal fin
pectoral fin
Killing saw
The sawshark belongs to
the family of fish without
bones. It has a unique
blade-like snout that is
edged with teeth. It uses
this to kill its prey.
caudal fin
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Friends and Enemies at Sea
Friends and Enemies at Sea
Symbiosis means ‘living together’. In a symbiotic relationship, two creatures can help
each other to survive. This help can be with finding food, protection, cleaning or
transportation. The larger creature is often the host, with the smaller creature living on
it. Sometimes, both creatures live independently and still help each other.
Q Can fish live in symbiosis with other
water creatures?
A The clownfish lives among the stinging
tentacles of sea anemones. This keeps it safe
from its enemies. When other fish come to
eat the sea anemone, the aggressive clownfish
drives them away. It also cleans algae off the
anemone. The clownfish is not harmed by the
stinging tentacles of the anemone because it
has a protective mucous layer surrounding it.
This relationship is called mutual symbiosis
because both members benefit from it.
Line up for a scrub!
There are a number of fish and
invertebrates, like shrimp, that act as
cleaners. These animals clean their hosts
of parasites and dead skin. They clean
the teeth, skin, gills and mouth of the
hosts. Different types of fish and even
sharks and stingrays come to the cleaners
for their services. In exchange, the
cleaners, some of which even enter the
mouth of the host, are not attacked, and
get a good feed!
Q Can a host be harmed?
A The pearl fish is a parasite which enters a
sea cucumber to feed on it. The sea cucumber
gets irritated by this and tries to rid itself of
the pearl fish by expelling it with its digestive
waste. Sometimes, the sea cucumber expels
most of its digestive tract with the effort. This
can seriously affect its health. This relationship
is called parasitism – one member benefits at
the expense of the other.
Q Do hosts and guests share their food?
A Sometimes, two animals share a home
and food. Crabs dig holes in the seabed and
the arrow goby fish burrows inside these
holes. The fish plays housekeeper by feeding
off the crabs’ waste. Another example is the
hermit crab, which picks up and places a tiny
sea anemone on its back. The anemone, with
its stinging tentacles, protects the crab from
other animals. In return, the anemone gets
free food when the crab eats.
Marine parasite
The pearlfish – found in
tropical and subtropical
waters around the world
– is responsible for more
sea cucumber deaths than
any of the cucumbers’
other predators.
Try these too…
Oceans (34–35), Whales
(56–57), Other Marine
Mammals (58–59), Fish
(66), Sharks and Rays
(68–69), Life of a Fish
(70–71), Origin of Life
(88–89), North America
(110–111), South
America (112–113),
Australia and Oceania
(114–115), Europe
(116–117), Africa
(118–119), Asia
(120–121), The Poles –
The Arctic and
Antarctica (122–123)
Another housekeeper
The spotted goby also has
a symbiotic relationship
with crabs.
67
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The Living Planet
Sharks and Rays
Sharks, skates and rays all have the same ancestors and are
among the oldest fish on Earth. They were here even before
the dinosaurs! These fish have cartilage or tough tissue instead
of bones, and they breathe through gill slits. They don’t have
scales; instead their skin is covered with small tooth-shaped
growths called denticles. The denticles give these fish a rough,
sandpapery texture if rubbed the wrong way.
Quick Q’s:
1. Which is the earliest
shark we know of?
The cladoselache is
the earliest shark-like
fish we know of. It
grew to over 2 metres
(6.5 feet) in length.
It lived during the
Devonian period,
well before the age
of the dinosaurs.
Q How big are sharks?
A There are over 350 species of shark
Ouch, what a stinger!
The sting ray has a sharp stinger on its tail. When
attacked it lifts its tail and stings its enemy.
in the ocean, and not all are large killers.
Of these, less than 50 species grow longer
than 2 metres (6 feet). One of the biggest
sharks is the gentle whale shark, which is
15 metres (50 feet) long and eats plants
and small shellfish. The smallest shark is
the pygmy ribbontail catshark at just
24 centimetres (9.5 inches) long.
which belong to the same family as sharks.
Rays look like sharks that have been flattened
out. They have flat, kite-like bodies that help
them to glide through the ocean.
Q How does a shark find its prey?
A Sharks and rays have a strong sense of
Q Can rays be dangerous?
A Rays come in all different sizes, and
smell and can sense blood in the water
hundreds of metres away. They usually find
their prey through their sense of smell. They
have a sharp sense of hearing. They also move
very fast through the water. While attacking,
an average shark can reach a speed of 19
kilometres per hour (12 miles per hour).
some are dangerous. The giant manta is
enormous, but harmless. Other rays can sting
or produce an electric shock to stun their
prey and enemies. The lesser electric ray can
transmit a powerful electric shock between
14 and 37 volts.
Q What is a ray?
A There are thousands of species of rays,
2. Are all sharks
aggressive?
No. The horn shark,
which is 1.2 metres
(4 feet) long, hides
under rocks during
the day and comes
out at night. It is a
timid shark that eats
only small fish and
crustaceans.
3. Do sharks ever
attack whales?
The cookie-cutter
shark attaches itself to
a whale and then bites
out a bit of its flesh
with its razor-sharp
teeth. However,
because cookie-cutter
sharks are small, the
whale is only slightly
wounded by this.
gill slits
dorsal fin
Size matters
The great white shark is 3.7–3.75 metres (12–16 feet)
long. The biggest great white shark on record was
7 metres (23 feet) long. These huge creatures are
ferocious predators. They eat fish, rays and other
sharks, as well as feeding on carrion (decaying
bodies of fish and animals).
eye
4. How long do sharks
normally live?
Sharks can live for
many years. The great
white shark can live up
to one hundred years.
mouth
pectoral fin
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Sharks and Rays
Q What is a ghost shark?
A The chimaera or ghost shark belongs to
the same family as sharks, and its skeleton is
also made of cartilage. Chimaeras have long
tails, which they use to prod the muddy
seabed for shellfish and other small prey.
Most chimaeras have a poisonous spine on
the upper part of their body that they use to
defend themselves. They have three pairs of
tooth plates: two pairs in their upper jaw and
one pair in their lower jaw.
Q What is the difference between a
chimaera and a shark?
A The chimaera is similar to the shark,
but it has a bit of skin covering its gill slits
called an operculum, whereas sharks do not.
Most chimaeras have a poison-filled spine in
front of their dorsal fins. The upper jaws of
chimaeras are fused to their skulls, while
those of sharks are not. Sharks have
replaceable teeth, but chimaeras have
permanent tooth plates. Chimaeras always
hatch from eggs. The female chimaera lays
large eggs in a leathery egg case, and the case
lies at the bottom of the ocean for anywhere
between six months and one year before the
eggs hatch. Some sharks lay eggs and others
give birth to live young. Sharks can lay up to
100 eggs, while those that give birth to live
young have one or two young at a time.
Deadly teeth
Sharks may have up to 3,000 teeth at one time. Various species of sharks have teeth of
different shapes and sizes. This great white shark has sharp, wide, wedge-shaped and
serrated teeth that allows it to catch and tear its prey.
Try these too…
Not quite a devil
Oceans (34–35), Whales
(56–57), Other
Marine Mammals
(58–59), Fish (66),
Friends and Enemies
at Sea (67), Life of
a Fish (70–71), Origin
of Life (88–89)
The manta ray is the largest type of ray. It
can grow to more than 5 metres (15 feet)
wide. It is sometimes called the devil ray
because of the horny cartilage on its head,
but it has no sting and does not attack
humans. These horns are actually fins
that guide plankton and small fish into
the mouth of the manta ray.
On the floor
Chimaeras live on temperate ocean floors. They are
related to sharks and rays.
69
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The Living Planet
Life of a Fish
A fish might have a nervous system and a brain, but it does not
have a cerebrum – the part of the brain that guides thought.
Most fish cannot see very far but they can distinguish between
colours. Flatfish have both eyes on the same side of their head.
The four-eyed fish has a piece of tissue separating each eye in to
two which helps it to spot its enemies better.
Quick Q’s:
1. How do pufferfish
get their name?
Pufferfish defend
themselves by puffing
their bodies up with
water until they are
round and look much
bigger and more scary
than they actually are.
2. Is size enough to
scare an enemy off?
If that doesn’t scare
their enemies, the
pufferfish poison
them. The poison,
tetrodotoxin, is
also found in the
blue-ringed octopus
and is 1,200 times
stronger than cyanide.
A pufferfish’s poison
can kill 30 people!
3. How can deep-sea
fish see in the dark?
Fish that live in
the deepest part
of the oceans are
bioluminescent,
meaning they glow
in the dark. Certain
chemicals in the body
of these fish produce
a glowing light that
helps them find their
way through the dark
waters. They also have
large eyes and feelers,
which help them to
locate prey. In fact,
it is because of these
glowing fish that the
deepest part of the
ocean is known as
the ‘twilight zone’.
70
Q Do fish have senses?
A Fish can smell and feel. They can taste
Q Can fish perform tricks?
A Some fish can fool their enemies with
their appearance. The sabre-toothed blenny
looks like the wrasse, which is trusted by
sharks and other fish because it cleans them
of parasites. The blenny imitates the wrasse to
trick sharks and larger fish. It swims up close
to them and then it bites off a piece of flesh.
with their mouths and tongues. They also
have an extra sense called electroreception
that allows them to sense light, chemicals and
vibrations. Fish do not have ears outside their
body, but sound vibrations travel to their
inner ears so they do have a sense of hearing.
Q Can fish fly?
A Some fish use large fins to help them
leap across the water, so that they look
like they’re flying. Flying fish can cover
30–50 metres (98–164 feet) in one
glide, travelling through the air at up to
60 kilometres per hour (37 miles per hour).
Hatchetfish, which live in the Amazon, have
wing-like pectoral fins which they beat as
they fly short distances.
wing-like pectoral fin
upward
pointing
eyes
dorsal fin
caudal fin
All blown up
The pufferfish, also known as a blowfish, has an
elastic stomach which it fills up with water in order
to inflate itself.
Hatchetfish
Hatchetfish are found in
seas worldwide but are
most commonly seen in
the western Pacific. They
are small and have large
tubular eyes. Their eyes
point upwards allowing
them to see fish in the
lighter waters above.
Hatchetfish live at great
depths, between 200 and
600 metres (660 and 1960
feet). Their bodies are
compressed and covered
in delicate silvery scales.
The large eyes gather the
faintest traces of light
that is available.
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Life of a Fish
Q Can fish change colour?
A Some fish use camouflage to stay safe.
The cuttlefish has yellow, red, black and
brown pigment sacs under its skin. When
it feels threatened, it sends a signal to the
colour sacs and they spread the colour of
the rock or sand the fish is next to through its
body. The fish blends into its background, so
that threatening predators cannot see it.
That’s some red herring!
Herring have a strange way of keeping in touch with each other at
night, when they can’t see each other because of the dark – they
break wind. The noise, called ‘fast repetitive tick’, is the herrings’
way of finding each other without their enemies catching on. The
herring gulps air at the surface of the water, and then lets it out
through a hole in its rear end.
Q Do fish defend their young?
A Most fish are happy to eat any fish eggs
and young they can find, even their own. But
in the case of some fish, like the bubblenest
builders, the male looks after the eggs and
the young, defending the nest from other
fish. With cichlids, both parents guard their
young and take it in turns to fan and blow
fresh water onto the eggs. They protect
their eggs and young from other fish and kill
any predators that come too close. Some
cichlids keep the young from one batch of
eggs close by to guard their siblings
from the next batch.
Big mouth
The shape of a fish’s
mouth is a good clue
to what the fish eats.
The larger the mouth,
the bigger the prey it
can consume. Fish have
a sense of taste and
are known to taste
something before
swallowing it if it
is not an obvious
prey item.
Q How do fish survive in freezing water?
A Fish that live in the freezing seas of
Antarctica have an anti-freeze chemical
(glyco protein) in their blood that prevents it
from freezing. This allows them to live in icy
water. This is the ice fish and cod’s survival
trick. Other Antarctic fish like barracuda,
skates, krill and lantern fish have blood that
circulates very slowly. This means that they
can save their energy and use it to stay alive.
Try these too…
Oceans (34–35), Whales
(56–57), Other Marine
Mammals (58–59), Fish
(66), Sharks and Rays
(68–69), Origin of Life
(88–89), Australia and
Oceania (114–115),
Europe (116–117),
Africa (118–119), Asia
(120–121), The Poles –
The Arctic and
Antarctica (122–123)
Colour me up
Cuttlefish are also known as chameleons of the
sea because they can change their colour at will.
71
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The Living Planet
Reptiles
The word reptile means ‘to creep’. Reptiles are cold-blooded
vertebrates (animals with a backbone). Most reptiles are
covered with scales or plates to keep their skin moist.
They breathe through lungs.
Quick Q’s:
1. Which are the largest
and the smallest
reptiles?
The estuarine
crocodile is more
than 7 metres (23 feet)
long. The smallest
reptile is the British
Virgin Islands gecko.
It is just 18 millimetres
(0.7 inches) long.
2. Can I outrun
a reptile?
Tortoises may be very
slow on land but some
reptiles are very fast.
The spiny-tailed
iguana can run at
35 kilometres per hour
(21 miles per hour).
Q Why do reptiles like the sunshine?
A Reptiles are cold-blooded animals. This
means that they need to bask in the sun and
warm up to get energy. Although reptiles love
the sun, they can overheat, and then they
have to move in to the shade and cool down.
If it gets too cold out, reptiles become slow
and need to sleep or hibernate until the
weather is warmer. Even in sub-tropical areas,
many snakes hibernate right through the
winter. The population of reptiles falls off as
one moves to colder regions.
Lizard of the Americas
The green iguana is
between 1.2–1.8 metres
(4–6 feet) long.
3. How many eggs do
reptiles lay?
Some tortoises lay only
one egg in a season.
Turtles lay about 150
eggs several times each
season. Snakes can lay
anything from three
to 100 eggs, while
crocodiles lay between
20–90 eggs at a time.
4. Would I find
reptiles at the North
and South Poles?
Most reptiles are found
in warm, moist areas.
Being cold-blooded,
they cannot live in the
freezing temperatures
of the polar regions,
with their long nights.
Reptiles need regular
sunlight to warm
themselves up.
72
Egg talk
Snakes search for a moist, warm and safe spot to lay
their eggs. Snake egg shells are soft and leathery, not
hard and brittle like birds’ eggs. Baby snakes are born
with a tooth, which they use to break out of the eggs.
They make a slit in the leathery shell with their tooth to
slither out.
Q Fish are scaly. Are they reptiles?
A A reptile’s scales are different to those
on a fish. A reptile’s scales are attached to
each other, and they are actually thick skin.
Fish scales, in contrast, are stuck to the top
of the skin. Blood vessels run through the
lower layer of a reptile’s skin, but not a fish’s.
As they grow, reptiles regularly moult, or
shed their outer layer of skin. Snakes and
worm lizards shed this layer of skin in one
piece. Other reptiles shed it in several
smaller pieces.
Q Which was the first reptile?
A The oldest known reptile was hylonomus.
Q Where are baby reptiles born?
A Some lizards and snakes give birth to
live young, but most reptiles build nests
and lay eggs in them. Most reptiles are not
caring parents, and they leave the nest once
they have laid the eggs, though the eggs
contain sufficient food for the baby reptile.
Fortunately, their hatchlings are born with the
ability to look after themselves, and when they
hatch, they already look like adults. Some
reptiles, however, do make good parents.
Alligators guard their eggs and help the
hatchlings when they come out.
It was around 25 centimetres (10 inches)
long. Reptiles developed from amphibians,
and the first true reptiles had a solid skull
with holes only for nose, eyes and a spinal
cord. These early reptiles gave rise to another
line called synapsids, which had another pair
of holes in their skulls behind the eyes.
Synapsids developed into mammals.
Q I’m feeling cold! Am I a reptile?
A Reptiles include crocodiles, alligators,
caimans, lizards, snakes, worm lizards and
turtles; but not humans!
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Lizards
Lizards
Colourful character
Lizards make up the largest group of reptiles. There are over
4,300 species of lizards. They have four legs, a long tail and
movable eyelids. A lizard’s lower jaw is
fixed to its upper jaw, while a snake’s
jaws are separate.
Q How do I know a
Open frill
lizard if I meet one?
A Lizards have dry, scaly
Chameleons have an amazing
ability – they can flush their
skin with coloured pigment.
This helps them to take on the
colour of their background
so they can hide from
their enemies. Some
chameleons can move each eye
separately, so they can see two
things at one time.
skin and clawed feet. When they
are in danger, many types of lizards
can shed their tail to distract an
enemy. A new tail grows back.
Q What do lizards eat?
A Most lizards eat insects. Some, like the
green iguana, are vegetarians. Bigger lizards,
like the gila monster, eat eggs and small
animals. The biggest lizards of all, the
monitors, eat small animals.
Q Are lizards poisonous?
A The gila monster of North America and
the beaded lizard of Mexico and Guatemala
are poisonous. Some of the other larger
lizards can bite, but they are not poisonous.
The komodo dragon’s bite poisons the victim’s
blood. Most lizards are not dangerous to
humans. In fact, they help us by eating insects.
Poisonous
The beaded lizard
found in Mexico
is a venomous
lizard.
Scary frill
The opened frill of the lizard
makes it look much larger.
Q Is that lizard wearing a bib?
A The frilled lizard of Australia has
two large frilly pieces of skin on both
sides of its neck. When in danger, its frill
fans out around its head and measures about
30 centimetres (12 inches) in diameter.
Q Which is the biggest monitor lizard?
A The fierce komodo dragon is the biggest
monitor in the world. It weighs about 135 kg
(300 pounds). Its mouth is full of poisonous
bacteria, and when it bites, the bacteria
poisons the blood of its prey, killing it.
Multipurpose tongue
Lizards use their tongue
to catch insects for
food. They also use their
tongue to wipe clean
their mouths and eyes.
Try these too…
Origin of Life (88–89),
Dinosaurs (90), North
America (110–111),
South America
(112–113), Australia
and Oceania (114–115),
Africa (118–119), Turtles
(74), Snakes (75)
Child eater
Komodo dragons are
huge and fierce. They
have even been known
to eat small children.
73
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The Living Planet
Turtles
Turtles and tortoises form another group of reptiles which
includes terrapins. Turtles usually live in the sea, and although
tortoises belong to the same family, they prefer to live on land.
Freshwater turtles are often called terrapins. The back of a turtle
is covered with a bony shell, and they have beaks but no teeth.
Quick Q’s:
1. How large can a
turtle become?
The leatherback turtle
can grow up to
2.4 metres (8 feet)
and weigh up to
870 kilograms
(1,900 pounds).
2. How long does a
turtle live?
The common snapping
turtle lives for about
40 years, whereas the
giant tortoise would
need a huge birthday
cake to fit about
170 candles!
3. Can I be friends
with a turtle?
Most turtles are
harmless. But the
common snapping
turtle that lives in ponds
and rivers can attack
people. Their bites,
however, are rarely fatal.
74
Q Why do tortoises have a shell?
A A turtle’s upper shell or carapace is
like armour. The flat lower shell is called
the plastron. A turtle can draw its head,
legs and tail in to its shell whenever
threatened. Other animals cannot break
open the shell and get to the turtle.
Q Can a tortoise swim?
A Tortoises have stubby, strong feet and
a heavy shell, which is why they move about
slowly. They live entirely on land. Although
a few species of tortoise can swim, most
of them cannot. Turtles, however, are
advanced swimmers, with webbed feet that
help them to paddle through water. Smaller
turtles do the most swimming. Larger turtles,
like snapping turtles, prefer to walk along
the floor of the river.
Q What does a turtle eat?
A Most sea turtles eat fish, crabs, shrimps
and jellyfish. The adult green turtle eats only
seaweed and algae, grazing in the sea like
cows do on a field.
Protective shells
Some tortoises and
turtles can fold their
necks under their
spine. But those living
in the southern
hemisphere fold their
necks to one side.
Q How does a turtle breathe?
A Turtles breathe using lungs like humans,
but they can survive for hours without
oxygen. When they are swimming, they
need to come up to the surface to breathe
periodically. Some, like the Fitzroy River
turtle, have a pair of air sacs near their
rear end, in which they store air when
they are underwater.
Box turtle
The box turtle has
a dome shaped shell
with hinges at the
bottom that closes
tightly for protection.
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Snakes
Snakes
Snakes are reptiles that developed from lizard-like ancestors.
However, unlike most lizards, snakes do not have legs. They have
transparent scales that cover their eyes to protect them. They
breathe with only one lung located on the right side of their
body. In most snakes, the left lung does not develop or is absent.
Q How do snakes eat if they do not
Q How does a snake hear a
have teeth?
snake charmer?
A Snakes have a flexible lower jaw. They
A If you were a snake you would not have
can open their mouths very wide and swallow
prey that is bigger than they are. After a big
meal, a snake moves very slowly, so that the
prey can be digested. Digestion needs so
much energy that some snakes, like the
Mexican rattlesnake, increase their
temperature by 14 °C (57 °F). Once
digestion is complete, a snake excretes
the hair and claws of its prey. Snakes
cannot digest plants.
any ear ache or trouble with cleaning ear wax.
This is because snakes don’t have external
ears, so they cannot hear like we do. However,
they have an inner ear that can feel vibrations
on the ground and in the air. When the snake
sways to a snake charmer’s instrument, it is
actually reacting to the vibrations of the
charmer’s movement, not to the sound the
instrument is making. A sleeping snake might
not wake up if you called it, but it would be
sure to feel the vibration in the ground if
you walked close by.
Q Do snakes shed their skin?
A As they grow, snakes shed
all of their skin. The skin comes
off like a sock, beginning at
the mouth. Snakes can only
shed their skin when the air
is moist. If the air is dry, the
skin does not come off.
This is dangerous for the
snake, since the
old skin can get
infected. Skin left
attached to the
tail can cut off
the supply of
blood to the tip
which can
cause it to
drop off.
New clothes
Look at the snake
shedding its skin starting
from the mouth. Snakes
shed their skin when they
have grown too large for
their old skin. Just as you
buy new clothes when
your old ones are too
tight, snakes too grow
a new, larger skin.
Try these too…
Reptiles (72), Lizards
(73), Venomous Snakes
(76–77), Constrictors
(78–79), North America
(110–111), South
America (112–113),
Australia and Oceania
(114–115), Africa
(118–119), Asia
(120–121)
One giant leap
Some snakes, like the Singapore paradise
tree snake, can glide as far as 137 metres
(449 feet) through the air. These snakes
jump off branches and can even turn 90
degrees in the air to chase their prey or
to move from tree to tree. This has led to
the legend that snakes can fly.
Snake charming
Snake charmers usually remove the
snake’s fangs before trying out their
tricks with them.
75
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The Living Planet
Venomous Snakes
There are over 2,500 types of snakes in the world. Of these,
only about 450 varieties are venomous, or poisonous. These
include vipers, cobras, mambas and sea snakes. Even poisonous
snakes will only attack if they feel threatened.
Quick Q’s:
1. Which snake has the
longest fangs?
The gaboon viper has
the longest fangs, which
can grow to lengths of
about 5 centimetres
(2 inches).
2. Which is the most
venomous snake in
the world?
The inland taipan,
a venomous snake
found in Australia,
is the most venomous
snake in the world. Its
venom is 400 times
more powerful than the
venom of a rattlesnake.
Cobras, however, kill
more people, because
they live near
populated areas.
3. Which snake is the
fastest in the world?
The black mamba
found in Africa can
travel at speeds of 19
kilometres per hour
(11.8 miles per hour.
This makes it the fastest
snake in the world.
4. How does the spitting
cobra get its name?
When threatened,
spitting cobras spray
venom into the eyes
of the enemy, causing
temporary blindness.
This gives the snake
enough time to escape.
Spitting cobras are
known to spit venom to
distances of about 2.5
metres (8 feet)!
76
Q Are fangs important to snakes?
A Venomous snakes inject poison into their
victims through their fangs. All venomous
snakes have a venom sac that is connected
to their fangs. When they strike the prey, the
venom sac is squeezed to release the venom,
which then travels through a hollow passage
in the fangs into the victim.
Q Why are the fangs of the cobra shorter
than those of the viper?
A Cobras and all the other snakes in their
family have short fangs. Unlike vipers, these
snakes cannot fold their fangs out of the way
when they are not being used. If the fangs
were too long, a cobra would injure itself
when it closed its mouth.
Fang
Poison teeth
Vipers, one of the most poisonous snakes, have only one
pair of fangs. Their fangs are longer than those of other
snakes.
Spitting snake
Notice (left) the cobra’s most recognizable feature – its
hood or flap of skin muscle that it can extend to scare
its enemies. The image on the right shows a cobra
spitting venom. The cobra produces neurotoxic venom
to kill its victims.
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Venomous Snakes
Dark brown or
black upper part
Oar-like tail that
helps it to paddle
in water
Bright yellow
lower part
Marine reptile
Sea snakes are found in
warm waters, mainly
around the coasts of Asia
and South America. They
have flatter heads than
other snakes, which help
them to swim.
Q How many kinds of venom do
snakes produce?
A There are two types of snake
venom. Snakes like the cobras produce
neurotoxic venom. This affects the nervous
system, paralyzing the victim and leading to
a quick death. Vipers produce hemotoxic
venom that affects the blood and organs but
does not kill immediately. As a result, doctors
sometimes have a chance to treat the victim.
Q How is a pit viper different from a
true viper?
A Both true and pit vipers belong to
the same family. However, pit vipers have
specialized heat-detecting organs, or ‘pits’
that are located between their eyes and
nostrils. These sensors help pit vipers identify
the differences in the temperature between
their prey and the surroundings, thereby
allowing the snake to hunt even in the dark.
Q Is the rattlesnake poisonous?
A The rattlesnake is a highly poisonous
Q How are sea snakes able
to live in water?
A Sea snakes have paddle-like tails that
help them to swim in water. They also have a
large lung that is almost as long as their body.
This enables them to stay underwater for long
periods. Sea snakes eat fish and other small
marine animals.
Rattle
The rattle is made up of hard scales from the tip of the
tail. Each time a rattlesnake sheds its skin a new rattle
segment is added.
Try these too…
Reptiles (72), Lizards
(73), Snakes (75),
Constrictors (78–79),
North America
(110–111), South
America (112–113),
Australia and Oceania
(114–115), Africa
(118–119), Asia
(120–121)
Venom to the rescue
Snake venom is rich in proteins, so
it is used to make different kinds of
medicines, including painkillers. Most
medicines used to treat snake bites are
actually made from snake venom.
pit viper found in parts of North America
and Mexico. Most species of rattlesnakes
produce the hemotoxic kind of venom, which
is extremely poisonous. The snake usually
warns its enemies and victims that it is going to
attack by shaking the rattle at the end of its
tail. The rattle is made up of a series of hard,
ring-like scales that are connected. Every time
the snake shakes its ‘rattle’, these scales move
across each other to produce a loud rattling
sound that scares most animals away.
77
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The Living Planet
Constrictors
Some non-venomous snakes, like boas and pythons, have a
unique way of killing their prey. They coil their bodies around
the prey and squeeze it until the prey suffocates to death. The
snake then opens its jaws wide and swallows the prey whole.
Snakes that kill their prey in this manner are known as constrictors.
Quick Q’s:
1. Are there diffeerent
kinds of python?
There are 25 different
species of pythons in
the world. They are
found in Africa, Asia
and Australia. All
species of pythons are
constrictors, and none
of them is poisonous.
Some pythons have
patterns on their scales.
2. Is it true that boas
and pythons can go
without food for
several days?
After a big meal, boas
and pythons do not eat
for several days. This
is because the digestive
juices in the snake’s
stomach take a long
time to digest the food.
3. Which is the longest
snake in the world?
The reticulated python
is the longest snake in
the world. An adult
reticulated python can
grow up to 10 metres
(33 feet) in length.
4. Why are royal
pythons also called
ball pythons?
The royal python is
a type of python
found in Africa. When
in danger the royal
python coils itself
tightly into a ball. This
ability has earned
it a second name –
ball python.
78
Q Is the anaconda a constrictor?
A The anaconda is a type of boa. In fact,
it is the only boa that lives in water. For this
reason, the anaconda is also known as the
water boa. Like all boas, the anaconda also
kills its prey by suffocating it. It usually lies
still in streams or swamps waiting for its prey
to come near. The snake then grabs the
unsuspecting victim with its powerful jaws
and pulls it underwater to drown it.
Heavy
Green anacondas are found in the rainforests of the
Amazon and Orinoco basins, and also in Trinidad.
Deadly coils
It is almost impossible for prey to escape once a
python has coiled around it.
Q What is special about the green
anaconda?
A
The green anaconda is the heaviest
snake in the world. An average green
anaconda that is about 6 metres (20 feet)
long, usually weighs a hefty 250 kilograms
(551 pounds). Some green anacondas are
believed to weigh more than 500 kilograms
(1,100 pounds)!
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Constrictors
Q How are constrictors able to swallow
prey as big as monkeys and deer?
A The jaws of constrictor snakes are like
rubber bands. They might look small but
they can be stretched to a large extent. This
is because the upper and lower jaws are
attached to ligaments instead of the skull.
This helps the snake to open its mouth
wide enough to swallow a monkey or
a deer whole.
Q Do all pythons have red eyes?
A Albino pythons have red eyes and
tongues. This is due to a condition called
albinism, when the snake lacks melanin –
a pigment that gives the snake its natural
colour. Albino pythons can be white, yellow,
orange or brown, but they all have red eyes.
All the colours
Different species of the rainbow boa come in a wide
range of colours. They live on the ground in the forests
of South America. The name is also used for the slender
boa, which has colourful markings on its body and is
kept as a pet in some countries.
Q Why are newborn emerald tree boas
red or orange in colour, while the adults
are green?
A When they are growing, emerald tree
boas change colour several times. They are
usually born red or orange. Within a year, the
young emerald tree boa turns golden yellow,
before finally becoming green. As the snake
grows older the green colour gets darker.
Adult emerald tree boas spend most of their
lives draped around branches during the day,
and hanging down from the branches at night
to hunt their food. This snake spends its
entire life in trees. Their dark green colour
helps to camouflage them. Emerald tree boas
are among the few snake species that do not
lay eggs but carry their young inside their
bodies until the time of birth.
Patient killer
Green tree pythons
spend hours or even
days perched on a branch
and hardly making a
single movement. But
when any potential prey
is within reach, this snake
can move very quickly
and coil itself around
the victim.
Try these too…
Reptiles (72), Lizards
(73), Snakes (75),
Venomous Snakes
(76–77), North America
(110–111), South
America (112–113),
Australia and Oceania
(114–115), Africa
(118–119), Asia
(120–121), Ancient
Americas (132), Incas
and Aztecs (141)
Snakes with legs?
Scientists believe that snakes evolved
from lizard-like creatures. Over millions
of years, these creatures lost their legs
until they began to slither on their bellies
like snakes. Pythons are living proof of
this theory. All pythons have two tiny
spurs (claws) towards the back of their
long bodies. These spurs are thought to
be the remains of hind feet.
Spur
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The Living Planet
Crocodilians
Crocodiles and their relatives are together known as
crocodilians. This group of reptiles includes alligators,
caimans and gharials. Crocodiles, alligators and caimans
are found in the rainforests.
Quick Q’s:
1. What is crocodillin?
Crocodillin is a
substance that is found
in crocodilian blood.
Scientists believe that
this substance could
cure some diseases
that cannot be treated
with antibiotics.
2. Which is the largest
crocodile species?
The saltwater crocodile
is not only the largest
of all crocodiles, but
also the largest reptile
in the world. This huge
reptile can be more
than 6 metres (20 feet)
in length and weigh
over 1,500 kilograms
(3,307 pounds).
3. Which is the smallest
crocodile?
It’s an alligator
There are two species of alligators – American and
Chinese. The longest alligator ever measured was
5.8 metres (19 feet) long. It was found in Marsh Island,
Louisiana, in the USA. The Chinese alligator is an
endangered species and lives only in the Yangtze
River valley.
Q Is that a crocodile or an alligator?
A Crocodiles and alligators might
look a lot like each other, but they
are in fact very different. The snout
of a crocodile is longer and
V-shaped, while the alligator
has a broader, U-shaped snout.
Another way to tell the two
reptiles apart is to look at their
teeth. The crocodile’s lower
teeth are visible even when the animal’s
mouth is closed. Crocodiles also have
special glands that help them live
in saltwater, while alligators can
survive only in fresh water.
Narrow-jawed crocodilian
The gharial is the second-longest of
all crocodilians – a large adult can be
7 metres (23 feet) long. Their long
narrow jaws are adapted to a diet
of small fish.
The dwarf crocodile
is exceptionally small.
Adult dwarf crocodiles
do not grow more
than 2 metres
(6.5 feet) in length.
4. How many kinds
of caiman are there?
There are six types
of caiman. The largest
is the black caiman of
the Amazon, which can
grow up to a length of
6 metres (20 feet). The
commonest is the
spectacled caiman,
which grows to an
average length of
2.1 metres (7 feet)
and can be found all
over Latin America.
80
Q
Why do crocodilians have
eyes on top of their heads?
A All crocodilians spend a great deal
of time in water. They usually lie submerged
so that their prey cannot spot them. But
they can keep a lookout for prey as they
cruise through rivers and streams, since
their eyes are placed on top of their heads.
Incidentally, crocodiles do shed crocodile
tears, as the saying goes. They do this to
clean their eyes, and not because they feel
sad for their victims.
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Crocodilians
Q Do crocodilians chew?
A Crocodilians cannot chew their food.
They usually tear off huge chunks of flesh
or swallow their prey whole, if it is small.
Once they have killed their prey with their
vicious jaws, crocodilians toss their heads
back so that the food falls in to their throats.
Q What is special
about the Egyptian
plover?
A The Egyptian
plover is a bird that
is believed to share a special bond with
the crocodile. The plover feeds on
parasites that live in the crocodile’s
mouth. The reptile is said to open its
mouth and allow the bird to clean its teeth
without harming the plover in any way.
It’s a crocodile
The Nile crocodile is one of three
crocodile species found in Africa. For
centuries, it has been both feared as a man-eater
and worshiped for its strength. Recently, a notorious
crocodile named Gustav, was living in the rivers near
Lake Tanganyika in Burundi, Africa. This crocodile,
held responsible for killing hundreds of people,
was last seen in 2005.
Latin American cousin
The caiman is the major
crocodilian found in
Central and South
America, especially in the
Amazon rainforests.
Try these too…
Reptiles (72), North
America (110–111),
South America
(112–113), Australia
and Oceania (114–115),
Africa (118–119),
Asia (120–121)
Sunbathing
Crocodilians are cold-blooded creatures, so they can often be
spotted basking in the sun. This helps them to raise their body
temperature and get energy. Most crocodilians bask more after a
meal as heat helps them to digest the food faster.
Q Do crocodilians make good parents?
A Crocodilian mothers are extremely
protective. They build nests to lay their eggs.
Unlike other reptiles, the female crocodilian
does not abandon her eggs. Instead, she
settles nearby her nest to keep predators
away. After the eggs hatch, the mother takes
her young along for a swim. Nearly all
crocodilians carry their young about in their
mouths. The mother looks after her babies
for about a year. Crocodile mothers can be
very aggressive if their babies are in danger.
81
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The Living Planet
Amphibians
Amphibians live on land and in
water. Of the 6,000 species of
amphibians, most begin their life in water. The skin of
an amphibian is thin and moist and helps the amphibian
to breathe, so they need to live in moist, damp places.
Quick Q’s:
1. What do frogs and
toads eat?
Frogs catch live prey
(mostly insects) by
darting out their
long, sticky tongues.
The marine toad eats
plants as well as other
dead animals.
2. Do toads have long
tongues like frogs?
Toads have shorter
tongues than frogs
and have to use their
wide mouths to catch
their prey.
3. Why do some frogs
and almost all toads
secrete poison?
Frogs and toads secrete
poison for safety. Most
poison-arrow frogs
and mantella frogs are
brightly coloured to
warn their enemies.
Some harmless frogs
copy this colouring
to protect themselves
from predators who
mistake them
as poisonous!
4. Can toads help out
in the garden?
Frogs and toads help
to keep insects in the
garden under control.
They eat snails and
slugs, which destroy
plants. They are also an
important part of the
food chain. Rats, foxes,
crows and hedgehogs
eat them.
82
Q How do amphibians give birth?
A Most amphibians are born in water,
where the eggs are laid. Although some frogs,
toads and caecilians give birth to live young
that look like adults, most frogs lay eggs in a
blob of jelly and most toads lay eggs in long
strips of gel. Some caecilians lay eggs in
burrows. Male frogs call loudly to attract
females to suitable water bodies such as ponds
At the start of the mating season, male frogs
eggs are a favourite food of other animals in
the water. So frogs lay enough eggs to ensure
that some survive.
Worm lookalike
Caecilians are amphibians that look
like giant earthworms or small
snakes. They live hidden in the
ground most of the time.
Most species have smooth,
dark skin. Their eyes are
covered by skin for protection
underground. They have two
tentacles on their heads. There
are 171 species of caecilians.
Most of them live in hot and
moist places around the world.
Q
What are the changes
that happen to amphibians
as they grow?
A
All amphibians are born
from an egg and grow into a
tadpole. As the tadpole grows, its eyes
grow eyelids and the creature learns to
see both in and out of water. But until
they become adults, they spend all their
time in water. Tadpoles of frogs and toads
lose their tails before they move
on to land and become adults.
Long tongue
Frogs have a long tongue hinged at the front of the
mouth. They flick this tongue out quickly to catch food.
Q Is it a frog or a toad?
A Frogs have longer legs than most
toads, which help them to take long leaps.
The hind feet of a frog are webbed, to help
it swim. Toads hop around and have
dry, thick, warty skin. Unlike most
amphibians, toads like to live in dry
places. Both frogs and toads have bulging
eyes covered by a transparent piece of skin
to keep their eyes moist. When frogs
eat, they close their eyes and
push the food down
their throat.
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Amphibians
Q Are amphibians safe to touch?
A Most toads and some salamanders
secrete a poison through their skin to defend
themselves against predators. Most frogs are
not poisonous, although rainforest frogs like
the poison-arrow frog are so poisonous that
some people tip arrows with its poison to use
for hunting.
Q How big are amphibians?
A Amphibians range
The familiar frog
With over 5,000 species, frogs are among the most
common animals in the world. They are found from
the warm tropics to the cold sub-arctic regions, but
most species are found in the tropical rainforests. Adult
frogs are equally comfortable in land and water.
in size from the tiny
9.8 millimetre (0.38 inch)
Brazilian gold frog to the
Japanese giant salamander,
which is 1.5 metres
(60 inches) long and
weighs 25 kilograms
(55 pounds). Amphibians
are found almost
everywhere on Earth,
even in the Arctic.
Highly poisonous
Most of the 220 species
of the poison-arrow frog
of Central and South
America are brightly
coloured to scare away
potential predators.
Try these too…
Reptiles (72), Lizards
(73), Turtles (74),
Dinosaurs (90), North
America (110–111),
South America
(112–113), Australia
and Oceania (114–115),
Europe (116–117),
Africa (118–119),
Asia (120–121)
Sing a song for her
Male frogs and toads have a special
pouch in their throat that helps them to
croak. The sound is amplified by one or
more vocal sacs, which are membranes of
skin under the throat or on the corner of
the mouth. Croaking loudly is a good way
to attract females in the mating season.
Some frogs and toads croak loudly to
scare other males away and can even puff
themselves out to look bigger.
83
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The Living Planet
Insects
Insects make up the largest group of creatures on Earth.
Eight out of every ten animals are insects. There are about
925,000 species of insects. Of these, there are about
5,000 species of dragonflies, 110,000 species of
bees and ants and 3,500 species of cockroaches.
Quick Q’s:
1. How many insects
am I standing on?
If you are in a field,
there could be dozens
of insects under your
feet. One acre can be
home to more than
400,000,000 insects.
100,000,000 collembola
(springtails) can live in
a square metre!
2. Can I eat an insect?
Some insects can be
poisonous. However, in
certain parts of the
world, people do eat
non-harmful insects,
such as ants, crickets
and grasshoppers, since
they are a cheap source
of protein. But they
have to be cooked in a
certain way before they
are safe to be eaten.
3. How long have
insects been around?
One insect fossil,
found in Russia, dates
back to more than 100
million years before
the first dinosaurs.
Cockroaches are also
older than dinosaurs.
4. How many babies
can one pair of
houseflies have?
In five months, one
pair of houseflies can
grow into a family of
191 x 1018 if all their
young live and
multiply. That is 191
followed by 18 zeros!
84
Long jump champion
There are more than
11,000 species of
grasshoppers. Some can
jump 20 times the
length of their
own body!
Q What is an insect?
A Insects are arthropods – animals
that have a protective cover or an
exoskeleton (a skeleton outside the body).
The exoskeleton supports the body and keeps
the soft inner organs safe. Since the skeleton
can’t grow with the insect, the insect has to
shed or moult the skeleton regularly, and a
new one grows back. Insects are the only
invertebrates (animals without backbone)
that can fly. Some insects such as cockroaches
and some types of ants grow wings when
they are adults. All insects have six legs.
Scorpions, spiders and centipedes are not
insects, since they do not have six legs.
True insects also have external mouths
and 11 abdominal segments.
Digging up the soil
Many insects, such as ants, make their homes by digging
up the soil. In the process, they move the soil around
and allow air to pass underground, which improves the
fertility of the soil. Using chemical insecticides doesn’t
only kill pests, it kills these beneficial insects as well.
Q What is an insect’s body like?
A In Latin, the word insect means ‘cut in
sections’. An insect’s body has three parts: a
head, a thorax, and an abdomen. The head
has a pair of antennae, eyes and a mouth.
The head is used for eating, to feel around
and to gather information. Some insects have
simple eyes like ours, but most have complex
eyes made up of six-sided lenses. The second
part of the body, the thorax, supports the six
legs and wings. The last part, the abdomen,
digests the food and helps the insect breathe,
since insects do not have separate noses
like we do.
Lady on a leaf
There are over
4,500 species
of ladybirds,
which are
also known
as ladybugs
and lady
beetles. They
help us by
eating pests.
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Insects
Not at prayer
The praying mantis is
easily recognized by
its resemblance to a leaf
and the way it holds its
antennae together, as if
it has its hands joined
in prayer.
Try these too…
thorax
abdomen
proboscis
Q How do insects breathe?
A Insects have spiracles (little holes)
on the sides of the thorax and abdomen.
Air enters through these spiracles and then
breathing tubes carry the oxygen all over
the body. The spiracles close when the insect
is in water, ensuring that the insect doesn’t
drown. However, insects have to come up
for air regularly when they are underwater.
Q Why do we need insects?
A There are many insects that help us.
Butterflies, ants, bees and wasps pollinate
flowers and help to grow new plants,
including fruit trees. Insects give us honey,
medicines, silk, lacquer and wax. Some
beetles eat dead animals. Some insects eat
other insects. Grasshoppers lay so many eggs
that if all of them were to hatch, they could
eat up most of our crops and plants. This
does not happen because there are other
insects that eat up most of the grasshopper
eggs. Agricultural scientists have been
breeding insects to keep pest populations
under control. This is better than using
chemical insecticides, which are poisonous
not only for insects but also for humans.
Scientists have also been using insects as an
ingredient for vaccines, for example in a new
trial vaccine against cervical cancer. However,
there are many insects that are undoubtedly
pests. Mosquitoes, bedbugs and lice drink our
blood and spread diseases. Others, like the
housefly and the tsetse fly, can make us ill.
Locusts chew up our crops. Termites and
borers eat up wooden homes and furniture.
Amphibians (82–83),
Insect Life (86–87),
Origin of Life (88–89),
Plant Life (96–97),
North America
(110–111), South
America (112–113),
Australia and Oceania
(114–115), Europe
(116–117), Africa
(118–119), Asia
(120–121)
Major pest
The mosquito is one of our
biggest pests. It has a painful
bite, and carries the germs of
major diseases like malaria.
Long and short
One of the longest insects is the stick insect, which is about
36 centimetres (14 inches) long. It belongs to the orthoptera
insect family, which includes crickets, grasshoppers, praying
mantids, leaf insects and cockroaches. Most stick insects are
females and they can lay fertile eggs without the help of a male.
When the eggs hatch, out come more females. The smallest insect
of all is the fairy fly, which is 0.17 millimetres
(0.007 inches) long and can fly
through the eye of a needle.
85
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The Living Planet
Insect Life
Most insects go through various stages of life. They are born
from eggs, and grow into a nymph or larva. The larva then
becomes an adult insect, also called an imago. Sometimes there
is a fourth stage in which the larva becomes a pupa before
finally becoming an adult. The changes an insect goes
through are known as metamorphosis.
Q Do all larvae snooze in a cocoon?
A The butterfly larva is one of the few
Short life
For most insects, the adult
stage of life is the shortest.
Quick Q’s:
1. How does a bee
become queen of
the colony?
Worker bees produce
royal jelly. When a bee
larva is fed a diet of
royal jelly, it grows into
a queen bee. All the
others in the colony
are fed royal jelly only
for about two days.
Then, they are given
pollen and nectar or
honey instead.
that makes a chrysalis or cocoon around
itself to rest in, while it grows into an adult.
Most other insects move straight from the
larva to the adult stage.
Q Do insects lay their eggs in a nest?
A Some insects lay their eggs inside plant
stems. Walking stick insects scatter their eggs
about on the ground, while certain beetles lay
their eggs on dead animals so that their larvae
have food when they hatch. A tarantula wasp
lays one egg on a tarantula spider.
Laying eggs
Insects such as butterflies lay their eggs on the
underside of leaves.
2. Why are dung
beetles so called?
Dung beetles use the
dung from plant-eating
animals by rolling it
into balls. This is where
these beetles lay their
eggs. The larvae feed
on the dung. The
beetles bury each ball.
Deep sleep
The larva stops
feeding and
undergoes drastic
physical changes during
the pupal stage. This
stage occurs only in
insects like butterflies
that undergo complete
metamorphosis.
Q What is the
life cycle of a
mosquito?
A Mosquitoes lay
their eggs in water. The larva is born in water
and feeds on tiny organisms just below the
surface of the water. It comes up periodically
for a breath of air. Mosquito pupae do not
feed but are more active than other insect
pupae. After a few days, an adult mosquito
emerges from the pupa, and spends the rest
of its life on land.
Growing up fast
The life cycle of a mosquito usually lasts for about
two weeks.
3. Are all insect eggs
round and smooth?
Some species of assassin
bugs lay eggs that have
spines. These eggs
hatch into larvae, which
are almost like adults,
but do not have wings.
86
eggs
larva
pupa
adult
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Insect Life
Try these too…
Q Do insects live with their parents?
A Most insects lay their eggs in batches
Amphibians (82–83),
Insects (84–85), Plant
Life (96–97), South
America (112–113),
Africa (118–119),
Asia (120–121)
and then fly away. The young, when they
hatch, live close to each other and feed
together. They find safety in numbers even
though their parents are not around to protect
them. Some adult insects meet up only when
it is time to breed, and move on after that.
Q How many insects live together?
A Many insects live in groups, swarms,
colonies or nests. A colony of ants can have
just 50 ants. One big nest in Japan had
1,080,000 queen ants and 306,000,000
workers in 45,000 smaller nests, each of
which was connected with the others. Some
insects, like locusts, live in swarms. One
swarm can hold 28,000,000,000 locusts. When
a locust swarm attacks a field, it’s bad news
for the farmer. Each locust weighs only about
2.5 grams (0.09 ounce). But an average
swarm has a weight of 70,000 tons!
Click and roll
Most beetles struggle to roll over when
they are upside down on their backs.
But not the click beetle. When it is
upside down or needs to get out of a
jam, it bends itself until a special spine
on its thorax snaps into place. Then the
beetle shoots into the air with a ‘click’
sound. This usually does the trick, since
when it falls back down, it lands the right
way up!
beetle on its back
ready to jump
bodyarching
muscle
Food for the young
Ladybirds mate in spring or summer. Adult females
then lay several eggs near a colony of plant-eating
pests like aphids, or greenfly. When the larvae
hatch, they feed on these insect pests.
Q Why do social insects have such
large families?
A
Insects that live in colonies are
known as social insects. Like with bees,
the members of ant and termite
colonies also have different functions.
With these insects, the queen lays eggs.
Other members of the colony are
known as workers. They go out to
gather food, while the soldiers protect
the colony. Laying eggs is important
work in a termite colony – one
queen termite can produce almost
30,000 eggs every day. A queen
bee can lay more than 1,000
eggs a day.
Leading the way
Worker ants usually
hunt for food and
then leave a trail
of scent leading
the other ants in
the colony to the
food source.
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The Living Planet
Origin of Life
The Earth was formed about 4.5 billion years ago. But the
earliest fossils found show that life on Earth only began about
3.5 billion years ago.
Quick Q’s:
1. Why is the coelacanth
called a living fossil?
The coelacanth is one
of the earliest known
fish that has survived
until today. It grows to
a length of 2 metres
(6.5 feeet). Until a
coelacanth was caught
by a fisherman off the
east coast of South
Africa in 1938, it was
thought to be extinct.
2. What are the
different ages in which
life formed?
Life began in the
Precambrian age.
Then came the
Palaeozoic age, which
saw the first plants,
most invertebrates,
the first vertebrates,
fish, amphibians, and
reptiles. The Mesozoic
age or the Age of
Reptiles was when
dinosaurs ruled the
Earth. This was also
when flowering plants,
birds, and some
mammals developed.
Humans only appeared
much later, in the
Cenozoic period.
3. Is there any new clue
on how life began?
Scientists have found
some animals among
the mixture of gases
that come out of
volcanoes. Much of
Earth was like this
when life began. So
any animal that can
live here may hold a
clue to the origin of
life on Earth.
88
Early Earth
Artist's impression of how the Earth
looked in the early days – mostly water,
a few volcanic islands, and dinosaurs
roaming the land, seas and sky.
Q What was the Earth like in the early days?
A When the earth began, it was hot, dry
and dusty. There was no oxygen. According
to some scientists, the blue-green algae were
the first living things to appear. They
produced their own food and oxygen using
sunlight – a process called photosynthesis that
plants use today. Slowly, the oxygen in the
atmosphere increased, and larger organisms
were able to develop.
Q Did life definitely start on Earth?
Q What was the first animal with a spine?
A Some scientists believe life didn’t begin
A The first animal with a spine was called
on Earth, but came from outer space. They
believe that a comet hit the Earth, carrying
the proteins from which living things are
formed. There are a number of theories
regarding the origin of life on Earth (or
in space), but none of them have been
proven yet.
Q When did the
first animals appear?
A
Between about 600
million years ago and 517 million
years ago, the first animals appeared
in the oceans. They had soft bodies.
These flat creatures were the
ancestors of sea anemones, sea
urchins, jellyfish and worms. They
were all invertebrates – animals
without a spine.
First spine
Artist’s impression of how the Pikaia probably
looked. This seahorse lookalike is important as
it was the very first vertebrate.
the pikaia. It looked like a flat worm and was
about 5 centimetres (2 inches) long. It swam
close to the sea floor, by twisting its body back
and forth and using its tail fin to steer. The
pikaia is now extinct.
Q When did the first fish appear?
A The pikaia was followed by fish
without jaws, so their mouths had to
remain open to catch plants and animals
as they swam by. Then, about 475 million
years ago, the coelacanth
developed jaws and
teeth. Since they could
eat more effectively,
these fish with jaws
grew faster. Amazingly,
coelacanths are still
around today!
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Origin of Life
Studying those that died ages ago
Scientists called palaeontologists
study the lives of prehistoric plants
and animals by looking at fossils.
When these animals and plants
died, soil settled on top of them.
Over time, this soil gradually
hardened into rock. This happened
again and again till there were
several layers of rock, with the
oldest layer at the bottom. The
print of the dead animal or plant
that died during a certain period
can be seen clearly on the rocks.
These prints are called fossils.
Fossils have helped us to discover
what life was like before humans
were around.
Q When did the first land creatures appear?
A As the seas filled with more animals
feeding on one another, some marine
creatures (including some fish) began to
move to land to escape their predators and to
get food more easily. Some of these creatures
developed into insects like mayflies and
dragonflies. They grew lungs and their fins
changed to legs. These were the very first
amphibians – animals that could live either
on land or in water. A typical animal of this
period was the acanthostega. It had four
stubby feet and looked like a lizard. It spent
most of its time on the shores of lagoons.
Clues to early forms of life
Stromatolites are stone structures that may have been
formed by organisms such as the blue-green algae, when
they cemented the sediments at the bottom of the sea.
Scientists have found fossilized remains of some very
early life inside stromatolites.
Try these too…
Oceans (34–35), Fish
(66), Amphibians
(82–83), Insects (84–85),
Plant Life (96–97)
Ancestor of amphibians
This armoured fish may have been the ancestor of
amphibians who first left the sea and started to move
on to land. Fins below the body
may be the precursor
to legs.
89
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The Living Planet
Dinosaurs
Dinosaurs get their name from the Greek words deinos,
which means large and scary, and sauros or lizard. These
fearsome reptiles ruled the Earth during the Mesozoic
era, which lasted from 248 to 65 million years ago.
Quick Q’s:
Q How did the first reptiles
1. What did the
dinosaurs eat?
evolve on Earth?
Despite their
reputation as violent
monsters, 65 per cent
of the dinosaurs were
vegetarian. They lived
around the same time
as the first flowering
plants were developing
on the Earth. But most
of the plants around
them were like ferns.
Some types of
dinosaurs, such as the
turanoceratops, had
special parrot-like
beaks with which they
could bite off the
needles from ferns.
A About 300 million years ago,
amphibians evolved into reptiles.
These reptiles continued to adapt
to their environment. They
developed a better way of breathing
than amphibians – amphibians breathe
by moving their throat muscles, but the
dinosaurs moved the muscles below the
rib cage and abdomen, just like us. As a
result, they could take in more air.
Q
Did the Earth look the same as it
does today?
2. Were the meat-eating
dinosaurs special?
A At the time of the reptiles, the Earth
Most meat-eating
dinosaurs were smaller
than their prey! But
they were faster, with
bigger and stronger
jaws, sharp teeth and
deadly claws that could
kill and then tear apart
the thick skin of
another dinosaur.
was hot and dry. There was just one landmass
since the continents had not yet formed,
and there was no polar ice since it was too
hot. Reptiles – some of them as long as
6 metres (20 feet) – roamed the land. These
primitive reptiles evolved into dinosaurs,
about 210 million years ago, towards the
end of the first part of the Mesozoic era.
3. Why is the
tyrannosaurus rex so
famous?
Tyrannosaurus rex,
also known as T-rex,
was one of the largest
meat-eating dinosaurs.
It could stand up to
a height of 12 metres
(40 feet). It weighed
between 5 and 7 tons;
that is five to seven
times the weight of an
average elephant.
90
Q
Aren’t dinosaurs from the Jurassic
period in time?
A The Mesozoic era was so long that it is
divided into three periods. The first is called
the Triassic period. It occurred 248–208
million years ago. Then came the Jurassic
period, 208–146 million years ago, when huge
meat-eating dinosaurs were in charge. Finally
came the Cretaceous period, 146–65 million
years ago, which saw the end of the dinosaurs.
Q Were dinosaurs always large?
A Early dinosaurs of the Triassic age were
not very large. Even the biggest did not grow
larger than 4 metres (13 feet) long. During
the Jurassic period, dinosaurs grew much
larger. The giant plant-eating dinosaurs of
this time, called sauropods, were 30–45
metres (98–150 feet) long.
Flying reptile
The pteranodon was one
of the largest flying
reptiles, with a wingspan
of up to 9 metres (30
feet). Its sharp beak
was toothless.
Q What happened
to the dinosaurs?
A Nobody is sure. But
many scientists think
volcanic eruptions led
to such a thick cover of dust over the Earth
that sunlight could not get through. This
meant that plants could not make food, so the
dinosaurs had nothing to eat, and they died.
Age of dinosaurs
The age of dinosaurs was so long that it is divided into
three periods by scientists.
MESOZOIC ERA
TRIASSIC
248-175 million
years ago
JURASSIC
175-130 million
years ago
CRETACEOUS
130-65 million
years ago
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Armoured Dinosaurs
Armoured Dinosaurs
Some dinosaurs had armour-like plates on their
bodies that protected them from predators and harsh
weather. Dinosaurs like the stegosaurus also had
a double row of plates on their back. The plates were
mainly used to keep dinosaurs cool, although they were
also useful for scaring off predators. Some other
dinosaurs had spines sticking out of their bodies to
scare other animals away, or to help during a fight.
Q What was unique about the ankylosaurus?
A The ankylosaurus family were planteating armoured dinosaurs that existed
during the Cretaceous period. But although
these animals did not eat meat, they could
still be vicious. They had club-shaped tails
with spikes at the end, which they used to
defend themselves. By swinging their heavy
tails, an ankylosaurus could seriously injure
any enemy that tried to attack it.
Q Which was the spiniest
armoured dinosaur?
A Kentrosaurus, which means spiked
lizard, had plates and spines sticking out of
its back. Instead of jaws, it had a spiky beak.
Kentrosaurus grew up to 5 metres (16 feet)
long and weighed about 2 tons, but its brain
was as small as a walnut.
Q Were there any other armoured
dinosaurs around?
A The ceratops family were plant-eating
dinosaurs with beaks, one or more horns and
muscular frills around their necks. The frills
may have been useful in supporting the neck
in earlier species, but later might have been
used to defend the neck while fighting. The
triceratops and protoceratops were the bestknown ceratops. From our point of view, the
funniest thing about the ceratops was that
these huge dinosaurs had beaks like the
parrots of today.
Three horns
This fossil of the skull and
ribcage clearly shows two
of the three horns with
which triceratops used to
defend themselves.
Try these too…
Origin of Life (88–89),
Plant-eating dinosaurs
(92), Meat-eating
Dinosaurs (93), North
America (110–111),
South America (112–113)
Protected to the eyelids
Q Why was the pachycephalosaurus special?
A The plant-eating pachycephalosaurus,
which means the thick-headed lizard, gets
its long name from its strange head. The
pachycephalosaurus had a dome-shaped head
that made it look as if it was wearing a tight
cap. Its skull was about 25 centimetres
(10 inches) thick and housed a tiny brain.
The pachycephalosaurus probably used its
thick head as a weapon when defending
itself from other dinosaurs.
91
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The Living Planet
Plant-eating Dinosaurs
Meat-eating dinosaurs like tyrannosaurus rex may
be the best-known dinosaurs. But plant-eating
dinosaurs were more numerous and included some
of the biggest dinosaurs that ever lived. The most
gigantic of these, known as sauropods, were very tall
with long necks.
Quick Q’s:
Q Which was the largest plant-
1. When did
sauropods live?
eating dinosaur?
Sauropods were
plentiful during the
Triassic and Jurassic
periods. Very few of
these gigantic creatures
survived into the
Cretaceous period.
2. What did the
stegosaurus use the
plates on its back for?
The stegosaurus
probably used its plates
to scare away its
enemies. Many
scientists think these
plates also helped the
dinosaur to regulate its
body temperature.
3. How big were
the plates on the
stegosaurus?
The largest plates on
the back of the
stegosaurus were
at least 60 centimetres
(2 feet) tall and wide.
4. What was unique
about the maiasaura?
Maiasauras were
duck-billed, planteating dinosaurs
that lived in herds of
10,000 or more. Unlike
all the other dinosaurs,
maiasauras were
believed to have
looked after their
offspring, just like
modern mammals.
92
A
Argentinosaurus, a sauropod,
was not only the largest plant-eating
dinosaur, it was probably the largest
dinosaur to have ever roamed the
Earth. This dinosaur is believed to
have grown to a length of about
40 metres (130 feet). It might
have weighed about 80–100 tons.
It had a long neck and tail, and a
small head.
Q
What unique features did
sauropods have?
A All sauropods were plant-eaters.
They had huge bodies, small heads, long
necks and strong legs. Sauropods had
chisel-shaped teeth that helped them to
grind leaves and other plants. Sauropods
were most noted for their size. Even the
smallest of sauropods were 6 metres
(20 feet) long.
Q Which is the most famous sauropod?
A Brachiosaurus is the bestknown member of the sauropod
group. Until recently this gentle
giant was considered to be the
largest dinosaur ever. This record
has now been broken by the
discovery of the argentinosaurus
fossil in South America.
Q Were sauropods the only plant-eating
dinosaurs?
A Apart from sauropods, there were
several other groups of plant-eaters.
Orbithopods had bird-like feet, beaks
and long, stiff tails. Ceratops had beaks,
one or more horns and muscular frills
around their necks. Stegosaurs had
armoured bodies with thick scaly skin
and spikes or plates along the back.
Ankylosaurus had hard armour-like skin
and a club-shaped tail, which was used
to drive its enemies away.
Largest land animal ever?
Argentinosaurus may be the largest land animal
ever, but there are others that may have been
even bigger. No one knows for sure.
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Meat-eating Dinosaurs
Meat-eating Dinosaurs
All carnivorous dinosaurs fell into the group called Theropods.
Some theropods were omnivorous, meaning they
ate both meat and plants. The theropods walked upright on
their hind legs and had short front limbs with sharp claws.
Of all the theropods, tyrannosaurus rex is the most famous.
Q Which was the largest meat-eating
Try these too…
dinosaur we know of?
Dinosaurs (90),
Armoured Dinosaurs
(91), North America
(110–111), South
America (112–113),
Africa (118–119),
Asia (120–121)
A Theropods were not as large as their
plant-eating cousins. However, some, like
tyrannosaurus rex and giganotosaurus, grew
to a length of about 12.5 metres (41 feet).
Scientists have recently discovered the
remains of what is now considered to be the
largest meat-eating dinosaur to have ever
lived – mapusaurus. This dinosaur is believed
to have been over 13 metres (42 feet) long.
Q Did T-rex really hunt down its prey?
A T-rex was built like a true predator. It
walked upright on two powerful legs, and had
a narrow snout that gave it a good view of its
surroundings. Like most predators, T-rex
had small eyes that faced forwards
giving the dinosaur a sharp view of its
prey. It also had a good sense of smell.
Despite these features, many scientists
believe that T-rex was mainly a scavenger
that hunted only when it was necessary.
Deadly claws
Velociraptors had a sharp, hook-shaped claw on each
foot. This claw was drawn into the toe when not in use.
Pricey fossil
In 1990, Susan Hendrickson, a fossil hunter, discovered the
largest fossil of a T-rex near Faith in South Dakota, United States.
The fossil was named ‘Sue’ after the person who discovered it.
Soon after its discovery, Sue was at the centre of a legal battle.
The bones were found on land that was owned by a private rancher.
The land was held in trust by the United States government. The
rancher claimed that the fossil belonged to him since he owned
the land on which it was found. This started a dispute over the
ownership of Sue. After a five-year-long legal battle, a judge ruled
in favour of the rancher, who later sold the fossil at a Sotheby’s
auction for a whopping 8.4 million dollars (about 4.6 million
pounds) – the largest amount ever paid for a fossil.
Q
What made the
velociraptor a good hunter?
A Velociraptor grew to a height of about
1 metre (3 feet) and was 2 metres (6 feet)
long. Its small frame made velociraptor fast
and agile. This dinosaur could chase its
victims at speeds of about 60 kilometres per
hour (40 miles per hour). Velociraptor may
also have hunted in groups, helping it to take
down even the largest dinosaurs of the time.
Big bite!
T-rex had 60 razorsharp teeth that
could grow up to
23 centimetres (9 inches)
long! Its huge jaws
could break the
backbone of
its prey.
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The Living Planet
Other Prehistoric Animals
Prehistoric animals are those that existed in the prehistoric
age, the time before recorded history began. Several animals,
including the woolly mammoth and the woolly rhinoceros,
roamed the Earth during these times. Some of these prehistoric
animals lived at the same time as the dinosaurs. Most of what
we know about them is from the study of their fossils.
Quick Q’s:
Q What animals other than dinosaurs
1. What is a
brontotherium?
lived during the Jurassic period?
Brontotherium means
thunder animal. It was
a large mammal similar
to a rhinoceros, with
a forked horn on its
snout. Many fossils of
this animal have been
found in South Dakota
and Nebraska in the
USA. Often, they were
found after the soil
covering the fossil had
been washed away by a
big rainstorm. That is
how the prehistoric
beast came to be
known as the thunder
animal.
A
The sabre-toothed cat, or smilodon,
was about the same size as an African lion.
Bones of almost 2,000 of these animals were
found near Los Angeles in the United States.
The smilodon had strong front legs and a
short tail. Its long teeth, from which it gets its
name, came in handy for hunting. The sabretoothed cat became extinct about
11,000 years ago.
Father of elephants
There were many types of
mammoths, some larger and
some smaller than the modern
elephant. Most mammoths had
curving tusks. The fossils of many
woolly mammoths have been
found in the Arctic regions.
2. What is a glyptodont?
Glyptodont was one
of the earliest forms
of the armadillo.
These curious animals
weighed over 1,000
kilograms (2,200
pounds) and their
bodies were covered
with armour about
5 centimetres
(2 inches) thick.
3. Were there
any prehistoric
flightless birds?
Phorusrhacos was a
fierce giant bird that
could not fly. It stood
2.5 metres (8.2 feet)
tall and some adults
probably weighed over
130 kilograms (287
pounds). It was one of
the largest birds ever.
94
sabre tooth
Q
What is a
mammoth?
A A mammoth is an ancestor of the Asian
elephant. Scientists think the first mammoths
developed in northern Africa around 4.8
million years ago. They had long, curved
tusks and some types were covered with long
hair during the last Ice Age. Mammoths
migrated from Africa to Europe, Asia and
even as far as North America.
Teeth as sharp as knives
The smilodon was a sabre-toothed cat with protruding
canines. There were six species of this extinct killer.
They could weigh up to 200 kilograms (450 pounds),
about the size of an average lioness. Smilodon fossils
have been found in North and South America. The fossils
of other sabre-toothed cats have been found in other
parts of the world. The earliest of these fossils have been
dated to 33.7 million years ago, while the most recent
sabre-toothed cat became extinct about 9,000 years ago.
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Other Prehistoric Animals
Half bird half dinosaur
The mysterious archaeopteryx lived in the late Jurassic
period, about 155-150 million years ago. The fossil
of this animal, which may have been the first ever
animal capable of true flight, has been found in
Germany. It was the same size as the magpie.
Q Could archaeopteryx fly?
A No one knows for sure if archaeopteryx
Q Were all mammoths woolly?
A The mammoth had to grow a woolly
coat when the world began to get colder,
about 700,000 years ago. But by the end
of the Ice Age, even the woolly mammoth
was extinct. The only survivor was the dwarf
mammoth, which died out about 3,500 years
ago. Some people believe that woolly
mammoths survived the Ice Age, but died
from disease or were hunted down for food.
could fly. Some scientists argue that the fossil
of archaeopteryx, first described in 1862, is a
fake. They believe that someone added the
impression of feathers to a small reptile
skeleton. But recent research has supported
the theory that archaeopteryx was a genuine
link between dinosaurs and birds. Fossils of
other feathered dinosaurs found in the Gobi
Desert of Mongolia and China are very
similar to the archaeopteryx fossil.
Try these too…
Seasons and Climate
(28–29), Oceans (34–35),
Volcanoes (36–37),
Earthquakes and
Tsunamis (38–39), Big
Cats (46–47), Elephants
(52), Seabirds (60), Birds
of Prey (61), Flightless
Birds (64), Origin of Life
(88–89), Dinosaurs (90),
Armoured Dinosaurs
(91), Plant-eating
Dinosaurs (92), Meateating Dinosaurs (93),
North America
(110–111), South
America (112–113),
Australia and Oceania
(114–115), Europe
(116–117), Africa
(118–119), Asia
(120–121), The Poles –
The Arctic and Antarctica
(122–123)
Is that a human?
The first humans appeared about 2.4–1.5 million years ago.
Called the Homo habilis, these people were only 1.3 metres
(4 feet 3 inches) tall. But they were much more intelligent than
the other animals. They made tools from stone, which they used
to hunt for food. Then about 130,000 years ago, the Neanderthal
man arrived in Europe. Neanderthals were about 1.7 metres
(5 feet 6 inches) tall and very muscular.
Q Was archaeopteryx a bird or a dinosaur?
A Archaeopteryx means ancient wing. It
was a prehistoric creature that had the features
of both dinosaurs and birds. It had broad
rounded wings and a long tail. Its feathers
were just like those of modern birds. But
archaeopteryx had a long jaw filled with sharp
teeth. Modern birds do not have any teeth at
all. Its claws were very different from the claws
of any bird we know of, they resembled the
claws of a dinosaur. Its tail was bony like that
of a dinosaur, not feathery like that of a bird.
Because archaeopteryx had half the features
of a bird and half the features of a dinosaur,
it is called a transitional creature.
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The Living Planet
Plant Life
Plants, of which there are about 350,000 species, are one of the
biggest groups of living things. They include trees, shrubs, vines,
ferns, grasses, mosses and lichen. Green plants can produce
their own food using a combination of water and nutrients from
the soil, and sunlight.
Quick Q’s:
Q What are the
1. Do ferns have
flowers?
different groups
of plants?
A fern has neither
flowers nor seeds.
Ferns grow from spores
on the leaves that are
scattered by the wind.
Each fern leaf can hold
750,000 spores.
2. Do some plants
eat insects?
The leaves of the venus
flytrap snap shut when
an insect touches them.
The plant then digests
the trapped insect
slowly, using enzymes
from its leaves. It
takes each leaf about
ten days to digest
one insect.
3. What are stilt roots?
Mangroves, tropical
plants that grow near
the coast, are partly
covered by the sea
water every time the
tide flows in. To keep
themselves above water,
they have stilt roots
which prop them up.
These roots can
breathe through
special pores. Salt can
be dangerous to the
plant, but the roots
filter the salt out.
Deadly trap
Insects are attracted to
the bright colours in the
leaves of the venus
flytrap. Once they are
inside, the leaf snaps shut.
96
Leaf
A
There are two
major groups of
plants – those that
produce flowers and
those that don’t. Both types
can be broken down into
many different groups,
including climbing plants
and water plants.
Stem
Root
Growing from a seed
A seed first sends out its roots
underground, and then its stem above.
Leaves that grow on the stem produce food.
Q Do all plants grow from seeds, or are
there other ways too?
A
Some plants grow from a part of the
parent plant, or from spores on leaves that are
scattered by the wind. But most plants grow
flowers, which are pollinated by insects. Then
a seed forms at its base. These seeds are then
scattered and grow into new plants.
Q What kind of environment is best for
plants to grow in?
A
Different plants have different needs,
but all plants need food. Most plants need soil,
air, water and sunlight to produce food. Plants
that grow in the water need lots of water and
little, or no soil. Plants that grow
in the desert are used to little or no water,
and would die if they were taken to
a rainforest. Moss and lichen that
grow in the Arctic region would
not survive in warmer climates.
Q
How do plants live in
a desert?
A Plants that grow in the desert
have to adapt to the scarcity of
water. So, to conserve water,
desert plants like cacti have few
or no leaves. They store water
in their fleshy stems. A
layer of wax, called a
cuticle, covers these
stems and does not
allow the water to
evaporate. Some desert
plants, like the ocotillo,
make the most of the
short rainy season to grow
as much as possible, and
then rest during the dry
season. Some desert plants grow
very long roots that reach down
deep into the ground
in search of water.
Slow-growing saguaro
The saguaro cactus can take up to
75 years to develop a side shoot.
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Plant Life
Q How do plants protect themselves from
their enemies?
A Since plants cannot run away from their
enemies, they devise their own protection.
Plants like the cactus have spines that protect
them from animals. The roots of the conifer
are often attacked by beetle larvae. But the
conifer has chemicals in its roots to attract
worms that eat up the larvae. The wild
tobacco plant uses the same tactic when it is
attacked by the hawkmoth. Its leaves release
chemicals, attracting killer bugs that eat up
the moths. Plants like the bleeding heart and
the Dhatura contain deadly poisons to kill
their attackers. Some, like the rose and
Himalayan blackberry, have thorns that stop
any animal that wants to eat it. Other plants,
like the stinging nettle, are covered with hairs
and release a chemical that irritates or ‘stings’
the mouth of the animal that eats them.
Sharp roots
The stilt roots of the
mangrove have
needle-sharp points,
making it difficult to
walk near the plant.
Try these too…
Seasons and Climate
(28–29), Food for Plants
(98), Trees and Shrubs
(99), Aquatic Plants
(100), Climbers and
Creepers (101)
What’s that smell?
Deadly dhatura
The dhatura plant, common in Asia, contains a poison
strong enough to kill humans.
The voodoo lily has a flower that smells like rotten meat. This
attracts flies to the plant. The flies and beetles carry pollen from
one flower to another and help fertilize the flowers so that new
voodoo lilies can grow. Rafflesia arnoldii has the largest flower
of any plant in the world – it is over 1 metre (3 feet) across. It uses
the same strategy as the voodoo lily to attract flies for pollination.
Q Can plants survive in the Arctic?
A Plants that grow in the Arctic tundra
(treeless plains), where the ground is
permanently covered in frost, have to survive
strong winds and snowstorms. The ground in
the tundra contains few minerals, so there is
not much food, either. The plants that grow
here lie low and are much smaller than
plants in other regions. While most other
plants grow best when the weather is warm,
plants in the tundra have had to adapt to an
environment where the temperature is often
below 10 °C (-50 °F). The dark colour of
their leaves helps tundra plants to absorb
maximum heat from the Sun. Some plants
even grow hairy leaves to stay warm.
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The Living Planet
Food for Plants
Plants usually have roots, stems, leaves, flowers, fruit and seeds.
The roots, stems and leaves help the plant produce food. The
flowers, fruit and seeds help the plant reproduce.
Root vegetables
Potatoes are the roots of the potato
plant. The plant stores its energy
in them.
Q
What are the various
functions of the roots?
A Plants grow from seeds or spores.
Quick Q’s:
1. Are the venus flytrap
and the pitcher plant
the only plants that
eat insects?
There are more
than 500 species of
carnivorous plants that
eat animals, including
butterwort and the
corkscrew plants that
grow in water.
2. How is the
slobbering pine
different from
other plants?
The slobbering pine
grows in dry, rocky
places. It has sticky
slimy leaves that
secrete so much
mucous that insects
drown in it!
3. How do other
carnivorous plants
attract insects?
The sundew family
of plants have stalks
on their leaves that
secrete nectar in order
to attract insects. The
insects are tricked into
slurping up this nectar.
Then the insects get
stuck to the leaves
and are digested.
98
With most plants, the roots grow first. They
hold the plant down and keep it steady.
They also absorb water and minerals from
the soil and transport them up so the plant
can produce food. In some plants, like the
banyan, aerial roots (roots in the air) grow
down from the branches to hold the plant
up. They grow thickly and look like a stem
or a trunk.
Q Where do the roots send the water to?
A The part of the plant that first grows
above the ground is called the stem. The stem
carries water and nutrients sent by the roots
up to the leaves.
Food factory
Leaves are the food
factories of plants.
They use chlorophyll,
a green pigment, to
make food.
Another carnivore
The pitcher plant has a deep cavity filled with a liquid
that attracts insects. The walls are built so that insects
can climb down but cannot climb up again. Slowly, they
drown in the liquid and are digested by the plant.
Q How do plants make their food?
A Leaves and green stems are the plant’s
‘kitchen’. They are green because they
contain a substance called chlorophyll. When
sunlight touches the leaves, chlorophyll
converts carbon dioxide and water into a
sugar called glucose. This is the basic food
for a plant. As plants produce food, they give
out oxygen, which all living things need to
breathe. There would be no life on Earth
without plants providing food and oxygen.
Q Why do plants grow flowers and fruit?
A Plants grow flowers and fruit to
reproduce. The flowers contain pollen,
which are carried by insects or the wind
to other plants for reproduction. The fruit
contains seeds of new plants, which are
carried by animals, wind or water to other
places where a new plant will grow.
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Trees and Shrubs
Trees and Shrubs
A tree is a large, woody plant that has one straight central stem,
called a trunk. It has branches that grow out of the trunk at
different heights. There are more than 50,000 species of trees.
A shrub is a woody plant that has lots of stems growing close
to the ground. Rhododendron, rose and hydrangea are
common types of shrubs.
Q How tall can a tree grow?
A Some trees grow extremely tall. In
1885, a eucalyptus was found in Australia
that measured 143 metres (470 feet). The
tallest tree alive today is a redwood called
the Stratosphere Giant. It was found in the
USA in 2000, and it is 112.7 metres (370 feet)
tall. That’s about as tall as a building 31
storeys high. The second tallest tree is in
the same place and is called the Federation
Giant. At 112 metres (368 feet) tall, it is not
far behind the leader.
Q How long do trees and shrubs live?
A Both trees and shrubs are perennial
plants, which means they live for more than
two years. Shrubs live for at least three years.
But trees usually live a lot longer. The oldest
tree in the world is a bristlecone pine,
nicknamed Methuselah, which is 4,767 years
old. It is named after Methuselah in the Bible,
who is said to have lived for 969 years.
Pretty shrub
The dwarf willow is a hardy shrub that lives in very cold
Arctic and sub-Arctic areas. It does not grow more than
6 centimetres (2.4 inches) above the ground.
Autumn beauty
Many trees, called
deciduous trees, have
leaves that change colour
in autumn and then fall
off. The tree has to store
food for the winter until
it grows new leaves in the
spring. Deciduous trees
are common in temperate
regions, and the beauty of
the multicoloured leaves
draws many visitors.
Q Why do some trees shed their leaves?
A Trees like birch, maple and oak and
shrubs like hydrangea that shed their leaves
every winter are called deciduous trees. Their
leaves are too weak to survive extreme cold.
But other trees stay green all year. Evergreen
trees like pines and firs and shrubs like yew
do not shed their leaves in winter. This is
because the leaves of evergreen trees are
coated in a wax-like substance that prevents
them from freezing.
Try these too…
Seasons and Climate
(28–29), Plant Life
(96–97), Aquatic Plants
(100), Climbers and
Creepers (101), North
America (110–111),
South America
(112–113), Europe
(116–117), Africa
(118–119), Asia
(120–121), The Poles –
The Arctic and
Antarctica (122–123)
Strangling to survive
The strangler fig, or banyan tree, produces
figs. Birds eat the figs and pass the seeds
out with their droppings on to the branches
of other trees. These seeds stick on to the
branches of a tree (called the host tree)
and send down roots. The roots of
the strangler fig grow thicker and soon
encircle the poor host tree. Then they
tighten around it, cutting off its flow of
nutrients. The host tree eventually dies,
while the strangler fig grows.
99
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The Living Planet
Aquatic Plants
Plants that live in water have developed special ways to survive.
They have grown so different from other plants that they cannot
live on land. Plants that live in water are called hydrophytes.
These plants are supported by water pressure. So they need a
less rigid structure than plants on land.
Quick Q’s:
1. Don’t any aquatic
plants have woody
trunks?
Aquatic plants do not
need hard, woody
stems. They let the
water around them
support their soft stems.
2. Are aquatic plants
of any use to us?
Aquatic plants are very
useful. The seeds of
the lotus can be eaten.
The leaves can be used
to wrap food in, rather
than plastic or
aluminium foil. A part
of the water chestnut
can be made into flour.
Some aquatic plants,
like the common
mare’s tail, are used to
make medicine for
healing wounds. Water
plants absorb methane,
which is a greenhouse
gas. They also release
oxygen into the air
while making food.
3. Are water plants
always good for
the pond?
The water hyacinth can
grow too fast, and
completely fill a pond
or small lake. It can
double in size in 12
days. At this rate of
growth, it can prevent
sunlight and oxygen
from reaching the
water, which can cause
fish and other plants
and animals to die.
100
Q Why don’t water plants sink?
A Water plants like lotus, water hyacinth
and lily have large, flat leaves that help them
stay afloat. All aquatic plants have fine hairs
on their leaves that trap air, and air sacks that
keep them buoyant. The water crowfoot has
large leaves on top, plus thin thread-like
leaves and feathery roots under water that
spread out and help the plant to float.
Q
Do water plants have the same roots
as land plants?
A Since the main purpose of roots is to
send water up to the leaves, aquatic plants,
whose leaves are always touching the water,
have smaller roots. In fact, aquatic plants have
very light, feathery roots since the roots do
not support the plant. These roots can take
in oxygen.
Beautiful and useful
Most parts of the lotus plant are useful. In Asia, it has
been cultivated as a food plant for centuries. The
flowers, seeds, young leaves and stems are all eaten.
Q Are aquatic plants special in other ways?
A Since aquatic plants are always
surrounded by water and do not need
to store it, their leaves only have a thin
skin (waxy coating) or none at all.
All plants have ‘breathing’ holes
under their leaves that release
excess water, but aquatic plants
have lots of these holes, and they
are always open.
Dangerous plant
The water hyacinth grows so fast that it can
choke most of the other life out of a pond.
It also provides an ideal environment for
mosquitoes to breed in. Originally from South
America, it has now spread all over the world.
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Climbers and Creepers
Climbers and Creepers
Climbing plants, also called vines or climbers, have developed
special ways of looking after themselves. They latch onto trees
or other supports and pull themselves up to reach the sunlight
at the top of the forest, which they need to make food.
Q How do climbers and creepers grow?
A Climbers have different ways of getting
around. Some make a few leaves grow into
thread-like coils or tendrils. Other climbers,
like roses, have hooks or thorns. These thorns
clasp the tree they are growing on (called the
host) and pull the rose plant up. Most
climbers have pretty flowers, which is why
they are often grown in gardens. Creepers or
ramblers do not even grow tendrils. They just
spread themselves over other plants or on the
ground. Some plants like bittersweet and
poison ivy grow as shrubs, and if they find
a host, they turn into climbers.
Q Do all climbers reach out towards light?
A A few rare vines climb away from light.
This is so that their tendrils can find the dark
bark of trees easily, and climb up them. All
climbers have softer stems than trees and do
not waste their resources in growing strong,
woody stems or branches. That is why they
can grow much faster than trees.
Green cover
People often grow
climbers to cover walls
with their beautiful green
leaves. The ivy is the most
popular plant for this
purpose. Many large
houses have had their
outer walls covered by ivy
for centuries. But we have
to be careful and ensure
that the climber does not
push deep roots in to the
wall, which can damage
the structure.
Q Do climbers have any enemies?
A In a rainforest, about 40 per cent of the
canopy can be covered by climbers. This robs
the trees of sunlight. Some climbers are so
heavy that trees can fall under their weight.
Trees have their own ways of keeping climbers
away. Some trees secrete unpleasant juices.
Palm trees drop their heavy, prickly fronds,
and the vines below are ripped off. Some, like
the gumbo-limbo tree, shed their bark so that
the creepers fall off with the bark.
Try these too…
Seasons and Climate
(28–29), Origin of Life
(88–89), Plant Life
(96–97), Food for Plants
(98), Trees and Shrubs
(99), North America
(110–111), South
America (112–113),
Australia and Oceania
(114–115), Europe
(116–117), Africa
(118–119), Asia
(120–121), The Poles –
The Arctic and
Antarctica (122–123)
Long lianas
Itchy plant
The poison ivy
is notorious
for inducing
an itchy rash
among most
people who
touch it. In
severe cases,
poison ivy rash
has to be
treated by a
doctor. This
versatile plant
can be a shrub,
a creeper or
a climber.
There are more than 2,500 species of
lianas or woody climbers. Most are found
in rainforests. Once a liana reaches the top
of the canopy, it spreads from one tree to
another. Some lianas are so thick, they
almost look like trees. Others grow more
than 914 metres (3,000 feet) long. Animals
of the rainforest use lianas to move from
tree to tree. Lianas twist upwards around
their host, or grow tendrils and thorns to
help them climb. Some even grow sticky
hairs to hang on!
101
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The Human Body
External Body Parts
The human body is operated by sensitive organs that are
kept safe inside the body. The parts that can be seen outside,
including hands, feet, skin, hair and nails, all have their own
uses in keeping us safe and healthy.
hair
skin surface
sweat gland
follicle
Q Why do we need hands?
A The human hand has five digits, four of
Colours of the world
A pigment called melanin
decides the colour of our
skin and our hair. Those
who have more melanin
are darker.
Quick Q’s:
1. How long does it
take a nail to grow?
On average, nails
grow 2.5 millimetres
(0.1 inches) in a month.
It takes one nail cell
3–6 months to grow
from the bottom to the
tip of the finger.
2. What is a lunula?
The lunula is a
crescent of pale skin
at the base of the nails.
which are called fingers, and one thumb. The
thumb helps us grip things better. The hand
also has a wrist, which links it to the arm. We
can move and bend our fingers because each
is made up of three separate bones. But the
thumb is not as flexible, since it has only two
bones. The fingertips have sensitive nerves
that tell us what we are touching. They warn
us when we are about to touch something
that might harm our skin.
Q What are feet for?
A Feet help us to balance and move. The
human foot is made up of the heel, instep,
sole, ball and toes. The ankle connects the
foot to the leg. The toes help us to get a
balance and a good grip while we walk. They
also push the foot off the ground at every
step we take. The ball of the foot is the
spongy part just behind the toes. The arch
and the heel absorb the shock of our feet
hitting the ground while we walk.
3. How much skin do
we have?
4. How many hair
follicles do I have?
102
Q What is skin?
A The skin is the largest organ of the
body. It holds all our other organs together.
The layer of fat underneath the skin keeps
our insides safe from injury. When the skin
is broken, germs can attack us. Skin secretes
an oil that keeps it soft and helps keep water
out. Under the skin are sweat glands, which
get rid of poisons that could otherwise harm
us. Skin is made of layers of cells. Every
minute, we lose 30,000–40,000 dead skin cells
which are replaced by new ones. New skin
grows from below and old, dry skin flakes off.
On average, almost all of our skin is replaced
every month. It is because skin replaces itself
that cuts can heal so quickly.
Q What about hair and nails?
A Hair and nails are made of a protein
An adult has more
than 2 square metres
(20 square feet) of
skin. This is almost
the size of a bed sheet!
The head has about
100,000 hair follicles
and the body has about
five million.
Skin deep
Skin is made of layers of cells that contain nerves, blood
vessels, hair follicles and glands.
All about balance
Our toes help us to keep balanced while we skip.
called keratin. Hair grows from a tiny opening
in the skin called a follicle. Nails grow from
the nail root, which is hidden under the skin
at the base of the nail. We have nails on our
fingers and toes even before we are born.
Under the nails are blood vessels that keep
the nails pink. Nails are hard and they
prevent the soft skin on the tips of our fingers
and toes from getting hurt.
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Bones and Muscles
skull
Bones and Muscles
The skeleton is like a scaffolding of bones inside us. It allows
us to sit, stand, walk, run and do everything else that we do.
Without it, we would be squishy, like jellyfish. The skeleton
gives our body a definite shape. It protects our organs, such as
the brain, heart, lungs, kidneys, spinal cord and liver. It also
supports our muscles.
Q How many bones do we have?
A A human baby is born with 270 bones.
Some of these join together as we grow and
by the time we are adults we only have 206
bones. The central part of our skeleton has
74 bones, including 26 bones in our spine,
22 in our skull and 25 in our ribs.
tough outer layer
compact bone
sponge bone
blood vessels
Bone structure
Bones have a tough outer layer to protect them. The
hard compact bone is connected to a sponge bone.
Our arms and legs have 126 bones – 62 in
our legs and 64 in our arms. Our ears have
six bones each. Bones are hard outside and
spongy inside. This is what makes them light.
Different parts of our body have different
types of bones. All together we have have
four kinds of bones: long, short, flat and
irregular bones. In some parts of our
body, there is cartilage instead of bones.
The cartilge is a rubbery connective
tissue. It is elastic and
fibres
helps in movement.
Muscle talk
Our muscles are made up of layers of
fibres, one inside the other. The thicker
fibres protect the thinner ones from any
damage when muscles are used. It looks
like thin wires inside thicker wires.
muscles that
move the arm
shoulder blade
ribcage
abdominal
muscles
spine
pelvis
Q What are muscles?
A Muscles are tissues
that can contract and
return to their normal
length. A muscle is made
muscles
of thread-like proteins in
that
our body. We have about
move
650 muscles. These muscles the leg
are connected to bones,
soft tissues such as cartilage
and ligaments, and to skin.
The muscles in our arms and legs
are long. Our chest muscles are
broad and flat. Our facial
muscles allow us to show our
feelings through expressions. We have more
facial muscles than any other animal. Muscles
are voluntary or involuntary. The voluntary
muscles move when we want them to. The
involuntary muscles, such as the cardiac
muscles in our hearts, move on their own.
Muscles
Muscles connect
bones to one
another and help
move the bones in
the direction we
want. They follow
commands sent
to them by the
brain through our
nerves. Different
muscles carry
out different
movements.
Try these too…
Digestion and Excretion
(104–105), The Brain
and the Senses (107)
Building muscles
outer layer of a
bundle of fibres
even smaller fibres
and threads
finest
muscle fibres
Muscles increase in
size if you exercise
them regularly. In
fact, strong muscles
show through the
skin in bumps.
If they are not
exercised for a long
time, muscles can
shrink in size and
grow weak.
biceps
contracts,
lower arm
raised
triceps contracts,
lower arm lowers
103
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The Human Body
Digestion and Excretion
Ever wonder what happens to all that food we eat? Where
does it go, and how does our body gain energy from it? Food
goes through an incredible journey from the moment we take
a bite. This process is called digestion and involves several
organs in the body.
inside space
outer layer
muscle layers
inner lining
Quick Q’s:
1. What role does
the tongue play in
our digestion?
The tongue has
millions of tiny taste
buds that help us to
identify whether the
food is salty, bitter,
sweet or sour.
2. What is the
alimentary canal?
The alimentary canal,
also called the digestive
tract, is a long tube
that starts at the mouth
and ends at the anus.
It includes organs, such
as the stomach, small
and large intestines
and rectum.
3. How does the
liver work?
The liver is not a part
of the digestive tract,
but it plays a vital role
in digestion. It releases
a substance called bile
that helps to break
down fat. The liver
also stores excess
fat for later use.
Q Why is it important to chew food?
A An adult human has about 32 teeth.
Some of these are used for biting and
tearing food, while others help grind it up.
The more we chew the easier it is for the body
to digest the food. As we chew, the mouth
releases saliva that moistens the food so that it
passes through the digestive system without
scraping any of the organs.
Q What happens to the food once we
104
Expanding stomach
An adult stomach is only as big as two fists, but it
stretches to twice its size when filled with food.
Q
swallow it?
Why do we sometimes choke on
our food?
A Once swallowed, the food moves
A The throat consists of two tubes – one
down the oesophagus, or food pipe, into
the stomach. The food pipe is a long tube
that connects the mouth to the rest of the
digestive tract. Wave-like motions of the
muscular walls of the food pipe help to
push the food down the long tube.
for food, and one for air. A small flap called
an epiglottis closes the windpipe the moment
we swallow, preventing the food from
entering the windpipe. However, sometimes
the food accidentally enters the windpipe,
causing us to choke. This usually happens
when we laugh or talk while eating, or swallow
food without chewing properly.
entrance to
nose from
the mouth
4. What does the
pancreas do?
The pancreas is located
behind the stomach.
This organ releases
chemicals that help
break down proteins,
fats and carbohydrates.
It also helps maintain
sugar levels in the body
and prevents diabetes.
glands
tongue
salivary glands
oesophagus
Early start
The process of
digestion begins the
moment we put food
in to our mouths.
Q Is the food digested in the stomach?
A The stomach walls churn and break
the food into tinier pieces. The acid in the
stomach kills harmful bacteria, while other
chemicals speed up digestion. Water, sugar
and salt are filtered into the blood through
the stomach walls. The undigested food,
called chyme, passes into the small intestine
for further digestion. The food is completely
digested in the small intestine. Small fingerlike projections, or villi, in the small intestine
pass the nutrients into the bloodstream.
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Digestion and Excretion
Q What happens to the undigested food?
A Undigested food like fibre moves
through the small intestine into the large
intestine. The water in the undigested food
is absorbed by the large intestine. Bacteria
present in the large intestine change the
waste material into faeces. The faeces are
sent into the rectum where they are finally
expelled through the anus.
Q What is urine?
A Urine is actually liquid waste. It contains
water and a harmful chemical called urea.
A pair of bean-shaped organs called kidneys
filter the urine from the blood. The urine
then passes into the urinary bladder through
two thin tubes, known as ureters. The
bladder stores the urine until it is passed
out through the urethra.
Down the pipe
Food takes about
eight seconds to
go down the food
pipe into the
stomach.
enamel
gum
mouth
blood
vessels
nerve
Inside the tooth
Our teeth are made up
of soft tissues and a
hard bony exterior.
food pipe
(oesophagus)
liver
blood vessels
A vital organ
Any problem in
the urinary system
can prove fatal.
stomach
pancreas
kidney
small
intestine
ureter
large
intestine
bladder
urethra
rectum
Long way to go!
The alimentary canal is about 10 metres
(30 feet) in length. Of this the small
intestine alone makes up for almost
5 metres (16 feet). Most of the food that
we eat takes about 20–30 hours to travel
from one end of the canal to the other.
This means that what we eat today is not
digested completely until tomorrow.
Try these too…
External Body Parts
(102), Bones and Muscles
(103), The Heart and
Circulation (106),
Reproduction and Birth
(108), Falling Sick (109)
105
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The Human Body
The Heart and Circulation
The heart is a muscle about the size of a fist that pumps blood to
every part of our body. It is inside our ribcage, a little to the left
of the centre of our chest. Blood carries oxygen and nutrients the
body needs. It also carries waste away that the body does not
need. This movement of blood is called circulation.
Quick Q’s:
1. How many times
does the heart beat?
The heart beats about
100,000 times in one
day. It begins beating
from before a child is
born and does not stop
until the person dies.
2. Does everyone have
the same kind of blood?
There are different
types of human blood,
so it has been divided
into four groups – A,
B, AB and O. Most
people have a blood
protein called rhesus
factor. This makes their
blood positive. People
who do not have this
protein have ‘rhesus
negative’ blood.
3. What is bone
marrow?
Bone marrow is the
soft tissue inside our
bones. It produces
blood cells. Since red
blood cells only live
for about 120 days
and white blood cells
only for a few days,
the bone marrow
works constantly.
4. Are there more red
blood cells than white
ones ?
Red blood cells make
up about 45 per cent
of our blood. There
is only one white blood
cell for every 600 red
blood cells.
106
Q How is the heart structured?
A The heart has four chambers,
two on each side, one above the other.
The two top chambers are called
veins
the left atrium and right atrium.
(blue)
The two lower chambers are the
left and right ventricles. A wall
of muscle separates the left and the
right sides of the heart. The right
atrium receives unclean blood
full of carbon dioxide from the
body. When the atrium is full,
a valve opens and blood flows
into the right ventricle below.
From the right ventricle, the
unclean blood is sent to the
lungs. The lungs breathe
out the carbon dioxide
contained in the blood
and breathe in oxygen
which the body needs.
The blood, now full
of oxygen, enters the
left atrium. When the
left atrium is full, the blood
flows into the left ventricle
from where it is
pumped to all
parts of the
body. This is
known as the
cardiac cycle.
Heart beat
Our heart beats
because
it is pumping
blood. Normally
it beats 72 times
in a minute.
Q What is the circulatory system?
A The heart, the lungs and the blood
vessels are part of the circulatory system.
Humans have about 100,000 kilometres
(62,000 miles) of blood vessels in their
body. This is enough to circle the
Earth two and a half times! Blood
vessels are made up of arteries,
veins and capillaries.
Q What is blood?
A Blood is sometimes
called ‘the river of life’
and it accounts for
heart about eight per cent
of our weight. Blood
contains two types
of blood cells. Red
blood cells give blood
its colour and also
help to carry
carbon dioxide
and oxygen to
arteries
(red)
and from the
lungs. White
blood cells
help to fight
infection and
they also help the
blood to clot if we are
wounded. The red and
white cells are suspended
in a fluid called plasma.
Food is also distributed
in the body by blood.
Veins and arteries
Blood vessels are made up of
arteries, veins and capillaries.
Arteries carry blood away
from the heart. Veins bring
blood back to the heart.
Capillaries connect
arteries to veins.
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The Brain and the Senses
The Brain and the Senses
brain
The brain, millions of nerves and the spinal cord make up the
central nervous system of the human body. All the information
gathered by sense organs like the eyes, ears, nose, tongue and
skin is processed in the brain.
Q What is the brain?
A The brain is an organ inside the skull.
It forms only about two per cent of our
bodyweight, but it controls our feelings,
movement, skills and every function necessary
to live. The human brain is divided into three
major parts; the cerebrum, the cerebellum,
and the brainstem. The cerebrum gives us
intelligence. It makes up 85 per cent of the
brain and operates voluntary muscles that we
have control over. The cerebrum is the area
of the brain that allows us to dance, jump
or solve puzzles. It also stores information,
which we call memory. The cerebellum or
‘little brain’ is below the cerebrum and is
just one-eighth of the size of it. The
cerebellum controls balance and tells the
muscles how to move. The brainstem
connects the rest of the brain to the spinal
cord, which runs down the neck and back.
The brainstem controls involuntary muscles
that work without us thinking about it, like
the heart, the lungs and the stomach.
Q What are the uses of smell?
A Smell is an important sense that our
nose helps to detect. Smell helps us to
examine the environment around us. Our
nose continuously tests the air we breathe and
alerts us accordingly. It warns us in case of
potential dangers like smoke or poisonous gas
or tells us about the presence of other people
or objects. Most importantly smell serves as a
recognition function. Each of us has a unique
smell and often we recognize one another by
smell. This is how even a new born baby
recognizes his mother!
spinal
cord
Brainy stuff
The brain processes
the basic information
that it gets from the
sense organs helping
us to see, hear, taste,
feel, smell and react.
Q How do we actually see?
A We see through our eyes,
of course, but it is due to our brain that
we know we are seeing this page and not
something else. When light enters our eyes,
special nerves inside the eyes carry a message
to the brain. Then the brain understands
what we are seeing. In the same way, it is
nerves
the brain that understands what we hear,
smell, taste or feel.
The brain grows on
Human brains are still growing. In
1860, the average weight of a male brain
was 1.36 kilograms (3 pounds). Today,
a male brain weighs about 1.44 kilograms
(3.17 pounds). Would you believe that
the human brain is also getting smarter!
cerebellum
skull
What nerves!
Thirty-one pairs of spinal
nerves connect the spinal
cord to the rest of the
body. They help to deliver
messages from the spine
to the rest of the body.
Try these too…
cerebrum
brainstem
External Body Parts
(102), Bones and
Muscles (103),
Reproduction and Birth
(108), Falling Sick (109),
Electricity (186–187)
107
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The Human Body
Reproduction and Birth
Like all other living creatures, human beings reproduce. Human
beings are mammals, so they give birth to live children.
fallopian
tube
uterus
ovary
egg
The female egg
Once puberty begins, the
ovaries produce one egg
(shown enlarged here)
roughly every 28 days.
This egg travels into the
uterus through the
fallopian tubes. The uterus
is connected to the vagina
through the cervix.
Quick Q’s:
1. How many eggs does
a woman have?
The ovaries hold
thousands of eggs.
These are released
once a month for
about 30 years during
menstruation. When
a woman is between
45–50, menstruation
stops and eggs are no
longer released. This
change is called the
menopause.
Q When can a human being reproduce?
A It takes several years before a human
being can reproduce. The body of a child
goes through changes between the ages of
about 8 and 15. This period is called puberty
and it makes a person ready to produce
children. Girls develop breasts and
their hips widen. Boys grow hair
on their faces and their voices grow
deeper. Other changes take place
in the reproductive organs.
placenta
Q What are reproductive organs?
A Male reproductive organs are
outside the body. They include the
penis, and a pair of testes inside a
cover called a scrotum. The testes
produce sperm and the male
hormone testosterone. During
sexual intercourse, sperm travels
down the penis. The female
reproductive system is also in
the pelvic region, but it is
inside the body. It is made
up of two ovaries, a uterus, two
fallopian tubes, the cervix and the
vagina. The ovaries produce a hormone
called oestrogen. They also make eggs
to join with the sperm to produce a baby.
head of sperm
2. For how many
years can the male
reproductive system
produce sperm?
Unlike females, males
can produce sperm
thoughut their life.
However, their fertility
declines a lot when
they are old.
108
tail
Sperm cell
The sperm cell
is either male
or female.
This factor
determines
the sex of
the baby.
uterus wall
Into the world
The baby develops in
the womb which backs
up against the uterus
wall. It comes out
through the vagina at
the time of birth. It is
still connected to the
mother through the
umbilical cord, which
has to be cut.
placenta
vagina
umbilical
cord
The miracle of pregnancy
The fertilized egg grows inside
the mother’s womb for about
40 weeks. This growth period is
called pregnancy. During
pregnancy, the baby gets food
and blood from the mother
through the umbilical cord
attached to its belly button.
The baby, or foetus, lies curled
up inside the womb in a position
known as the foetal position.
umbilicial cord
uterus
vagina (baby comes
out from here)
Q How is an egg fertilized?
A Each of us starts from
a tiny cell. Millions of sperm
cells are suspended in a mixture
called semen. The male body
has to produce lots of sperm,
since many of them die inside
the uterus. One sperm cell from
the father joins an egg cell from the
mother. These form a new cell in the
mother’s fallopian tube. This is called
fertilization. The fertilized egg then attaches
itself to the uterus wall and prepares
itself for growth. This is the
beginning of a baby.
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Falling Sick
Falling Sick
When we feel good and the body and the mind are working as
they should, we are in good health. When we have trouble with
any part of our body, we usually feel ill.
Q Why do people fall ill?
A The human body is made up of many
Q What food does the body need?
A The body works best when it is fed a
organs and systems. The organs include
the brain and the heart, the liver, the lungs
and the kidneys. If even one of these organs
does not do the work it is supposed to
do, we can fall ill. To work well, the body
needs the right kind of food in the right
quantities. It also needs exercise and a
clean environment. Any imbalance in
these factors can cause us to fall ill.
balanced diet with food from each of the
five basic food groups – carbohydrates,
vitamins, minerals, proteins and fatty acids.
We get carbohydrates and starch from
grains and cereals, potatoes and beans.
They give us energy. We get vitamins from
fruit and vegetables. Milk, cheese, yoghurt
and other dairy products give us calcium,
a mineral that strengthens bones and teeth.
Fish, meat, poultry, eggs, nuts and pulses
give us protein for building up our bodies.
Butter, oil, chocolate and sugar give us
fatty acids that contain the important vitamin
E to protect our internal organs. Healthy oil
comes from fish, nuts and vegetables.
Exercise for health
Physical activity, which includes jumping,
running, playing games, dancing and
other kinds of exercise, keeps our bodies
and minds healthy. It builds up muscles
and strengthens bones. Physical activity
makes us breathe deeply, and our lungs
get more oxygen. It keeps the heart
healthy and our weight in check. If you
eat more food than you use up with
exercise, the body stores this extra
energy as fat. Too much fat can be
harmful to our health.
Q What are germs?
A Germs are tiny creatures that we can
only see through a microscope. These include
bacteria and viruses. Harmful bacteria cause
infections like sore throats and stomach
upsets. Viruses are germs that can cause
chickenpox, measles and influenza. We catch
germs from people who are unwell, from stale
and unhygienic food or water, or from our
surroundings. They produce poisons that
make us sick. Some of these diseases, like
cholera, tuberculosis and HIV/AIDS can
even kill us.
Keep the doctor away
Fruit and vegetables are
rich sources of essential
vitamins. Eating at least
five portions of fruit
and vegetables per day
gives us the vitamins
and minerals we need
to stay healthy.
Modern diagnosis
A modern CAT scan
machine can map the
electrical impulses within
the brain. It is used to
locate any disease in the
brain or in the nervous
system. Similar modern
methods have made the
doctor’s job easier.
Try these too…
External Body Parts
(102), Bones and
Muscles (103), Scientific
Revolution (150–151),
The World after World
War II (160–161), The
New Millennium – 21st
Century (163)
The fighter
The image shows white blood cells (centre) surrounded
by red blood cells. The white blood cells are the fighters
we have within us. When germs attack, the body raises
its temperature to kill them. The white blood cells attack
the germs, surround and eat up the germ cells, and help
us to get healthy again.
109
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Continents, Countries and People
North America
North America lies north of the equator in the western
hemisphere. It is connected to the the continent of South America
by the narrow strip of land called the Isthmus of Panama. North
America has the Arctic Ocean to the north, the Atlantic Ocean to
the east and the Pacific Ocean to the south and west. It covers an
area of 24,480,000 square kilometres (9,450,000 square miles),
which is a little less than 5 per cent of the Earth.
Quick Q’s:
1. What languages
are spoken in
North America?
The United States has
no official language
but most people speak
English and many
speak Spanish. In
Canada, the two
official languages are
English and French.
But Spanish is the
official language
in Mexico.
2. Where is
Niagara Falls?
Niagara Falls is on the
river Niagara, between
Canada and the United
States. It is really three
falls – the American
Falls, the Canadian or
Horseshoe Falls and
the Bridal Veil Falls.
In one minute, more
than 168,000 cubic
metres (6 million cubic
feet) of water falls over
its crest.
3. Where are the
Great Lakes?
The Great Lakes
include Superior,
Huron, Erie and
Ontario, on the border
of Canada and the
United States, and
Lake Michigan in the
USA. Together, these
lakes make up the
largest freshwater
surface in the world.
110
North America
Q Which countries make up
North America?
A North America is made up of three
countries. Canada, the largest, is in the north,
followed by the United States of America in
the middle and Mexico in the south.
North America
The third largest continent after Asia and Africa, North
America had a population of 514.6 million in 2006.
Q What are the main geographical regions Q What are the types of animals that live in
in North America?
A There are four principal geographical
regions in North America. These include
the Appalachian Mountains in the eastern
United States and the Great Plains, which
stretch from the Gulf of Mexico in the south
to the northern parts of Canada. The other
regions are the West, where the Rocky
Mountains are found, and beyond the
Rockies, the low-lying Great Basin.
Q Who discovered America?
A Native Americans have been living in
the continent for thousands of years. Viking
sailors may have reached there around
1000 AD, but no proof of this has yet been
found. Most historians credit the discovery
of America by Europeans to Christopher
Columbus, who sighted land on 12 October
1492 while sailing west from Spain across the
Atlantic Ocean. Columbus thought he had
reached the shore of India, and that was why
he named the locals Indians. The island he
first sighted was San Salvador in the Bahamas.
North America?
A
Animals found in the prairies include
cougars, coyote, badgers, bobcat, prairie dogs,
foxes and American bald eagles. The tundra
(cold plains) is home to a few animals like the
grey wolf and snowshoe rabbit, while birds
visit the taiga (subarctic forests) to nest in the
summer. The lynx, minks, red deer, elk, and
moose can also be found in these regions.
The desert in the south is home to a variety
of insects, snakes, antelope and kangaroo rats.
Grizzly bears and rattlesnakes are also found
in different parts of North America.
Feared and hated
The rattlesnake is highly poisonous but warns its enemy
by rattling a special set of bones in its tail.
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North America
Q Who are the various people who live in
North America?
A
The first humans in North America could
have been there as long as 50,000 years ago.
They were probably related to the prehistoric
Kennewick Man, the name given to a 9,000year-old skeleton found in Kennewick,
Washington in 1996. Different Native
American tribes have claimed the remains
as theirs to prove that they were the first
Americans. The populations of these tribes
dwindled and after the arrival of the
Europeans, some were completely wiped
out because of war, disease and losing their
homes. When the Europeans had made
North America their home, they
began bringing African slaves,
many of whom remained in
North America after they
were freed. Today North
America is home
to people from all
over the world.
Cat with many names
Cougar, mountain lion,
puma – these are just
some of the many names for
this large, solitary cat found
all over North America.
Rocky road
The Rocky Mountains run from north to south through
much of the North American continent.
Popular food
Tortilla, or Mexican bread,
is now popular all over
the world.
Try these too…
Earth’s Atmosphere
(26–27), Seasons and
Climate (28–29),
Mountains, Valleys and
Caves (30–31), Other
Landforms (32–33)
A grand creation
The Grand Canyon is a steep gorge in Arizona in the United States. It has been shaped over two billion years
by wind and water, where the Colorado River cuts through the Colorado Plateau. It is almost 1.6 kilometres
(1 mile) deep in some places. It is about 446 kilometres (277 miles) long, and between 0.4 and 24 kilometres
(0.25 and 15 miles) wide.
111
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Continents, Countries and People
South America
Most of the continent of South America is in the southern
hemisphere, and the equator passes through it in the north.
To the west lies the Pacific Ocean, and to the north and to the
east is the Atlantic Ocean. It is 17,840,000 square kilometres
(6,890,000 square miles) – almost 3.5 per cent of the Earth.
This makes it the fourth largest continent. It is about two and
a half times the size of Australia.
Quick Q’s:
1. Which is the highest
peak in South America?
The Aconcagua peak
rises 6,960 metres
(22,834 feet) in the
Andes range in western
Argentina. It is the
highest peak in the
western and southern
hemispheres, the
highest in the world
outside Asia.
2. Which is the
highest waterfall in
South America?
Angel Falls on Auyan
Tepui river in
Venezuela falls 979
metres (3,212 feet). It
is the highest waterfall
in the world. It is
named after James
Crawford Angel, who
first saw it from his
aeroplane in 1933. The
local name is Churún
Merú, which means
Devil’s Mouth.
3. Which is the longest
mountain range in
South America?
Stretching for 7,000
kilometres (4,400
miles), the Andes is
the longest mountain
range in the world.
It starts near the
equator and goes on
almost to Antarctica. In
some places, it is
500 kilometres
(300 miles) wide.
112
South America
Q
How many countries make up
South America?
A The 12 countries in South America are
Argentina, Brazil, Bolivia, Chile, Colombia,
Ecuador, Guyana, Paraguay, Peru, Suriname,
Uruguay and Venezuela. French Guiana is
controlled by France. The Galapagos islands
in the Pacific Ocean are a part of Ecuador.
Q What are the main geographical regions
in South America?
A In the north and west are the Andes, the
second highest mountain range in the world.
On the eastern coast are the lower mountains
of the Guiana plateau, the Brazilian massifs
and the Patagonian plateau. The most
important lowland is the Amazon Basin, with
the world’s largest rainforest.
World Heritage
The historic centre of Salvador
de Bahia in Brazil is a UNESCO
World Heritage Site.
Varied geography
South America contains tropical rainforests, high
mountains, temperate grasslands and sub-polar regions.
Chile is home to the world’s driest desert – the Atacama.
The Andes mountains are home to the highest lakes
in the world.
Q
What types of climate are found in
South America?
A With the equator passing through the
continent, much of South America has a
warm and tropical climate, with wet summers
and dry winters. The northern coasts of
Venezuela and Colombia are dry and prone
to droughts. The Pacific coasts of Colombia
and Ecuador have a tropical climate, but the
coastal regions in Peru and northern Chile
are very dry. The cold currents off these
shores do not carry moisture. In the high
Andes mountains there is an alpine climate,
and the areas around them are cool. South
of the tropic of Capricorn, the climate is
temperate – summers are cool and winters are
cold. Patagonia in southern Argentina has an
almost polar climate.
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South America
Q What vegetation grows in South America?
A South America has the largest rainforest
in the world, which lies along the equatorial
region. Palms, tall trees, ferns, bamboos, and
lianas (vines) grow there. There are also large
areas of savannah, where tall grass grows.
This gives way to the brushlands along the
Venezuelan coast. Brazil has both deciduous
and evergreen forests as well as prairie (grassy
plains). The Pampas of Argentina are the
largest grasslands in South America.
Q What are the main animals found in
South America?
A South America has animals that
are special to the continent. These include
bloodsucking bats, the spectacled bear
and the tapir. South America is famous
for its alpacas and llamas. It also has jaguars,
anteaters and coati. The rainforests are home
to hundreds of species of birds, including
macaws and 500 types of hummingbirds.
The more unusual birds include the rhea
and the flamingo. Rainforests are also home
to snakes like the anaconda and other types
of boas, as well as iguanas and crocodiles.
The green anaconda, the largest boa, can
grow up to 10 metres (33 feet) long. The
Galápagos Islands, near the coast of Ecuador
in the Pacific Ocean, are known for their
unique animals like the Galápagos tortoise.
World’s largest
tortoise
An adult Galápagos
tortoise can weigh
300 kilograms
(661 pounds)
or more.
When it’s that huge, it’s Amazonian!
In terms of the amount of water it carries, the Amazon is the
largest river in the world. It starts in Peru in the Andes and flows
into the Atlantic Ocean after crossing into Brazil. Tributaries from
Bolivia, Colombia and Ecuador join it. Along its banks are 6,000,000
square kilometres (2,300,000 square miles) of rainforests. These
forests contain about 2,000 species of birds and mammals, several
thousand varieties
of plants and almost
2.5 million types of
insects. It was given
its name after a battle
that Spanish explorer
Francisco de Orellana
fought with a tribe of
Tapuyas women. They
reminded Orellana
of the ancient female
warriors or Amazons
of Greek mythology.
Tango in harmony
Various styles of the tango dance developed in different
parts of Argentina and Uruguay. It is now popular all
over the world.
Delicious food
Shrimp stew in a mud pot
– a typical dish of Brazil.
People from all over
the world brought their
cuisine to South America.
Try these too…
Earth’s Atmosphere
(26–27), Mountains,
Valleys and Caves
(30–31), Other
Landforms (32–33),
Oceans (34–35),
Volcanoes (36–37)
113
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Continents, Countries and People
Australia and Oceania
Oceania is a group of about 10,000 islands that lie in the Pacific
Ocean between Asia and America. It includes the continent of
Australia. Unlike the other continents, Oceania is a region linked
by water rather than land. It was given its name in 1831 by
French explorer Dumont d’Urville.
Quick Q’s:
1. How crowded is
Australia?
Australia is the sixth
largest country in the
world, but it has the
lowest population
density, with only two
people living in every
square kilometre.
2. What is special
about Australian sheep?
Australia has more
than 101 million
sheep. Most of them
are merinos which
produce an excellent
light wool. They give us
more than 70 per cent
of the world’s wool.
3. What is a dingo?
The dingo is a wild dog
of Australia. The dingo
fence, which keeps
sheep safe from
dingoes, is the longest
continuous fence in
the world. It is 1.8
metres (5.9 feet) high
and runs through
Queensland for
5,531 kilometres
(3,437 miles).
4. What is special about
Hawaii?
Except for Easter
Island in the South
Pacific, Hawaii is
furthest from any other
body of land. These
volcanic islands are still
expanding as more lava
pours into the seabed.
114
Australasia
Q
Other than Australia, what are the islands
included in Oceania?
A Oceania has four regions: Micronesia,
Melanesia, Polynesia and Australasia. These
regions are divided into thousands of islands.
Fiji, Indonesia and Papua New Guinea are
in Melanesia. Micronesia is a chain of tiny
islands that forms the Federated States of
Micronesia. The Cook Islands, Samoa and
Tonga are in Polynesia. Australia, New
Zealand and Christmas island are part of
Australasia. Hawaii, in the middle of the
Pacific ocean, is also part of Oceania.
Q Why is Christmas Island so-called?
A Christmas Island was given its name by
the British captain William Mynors of the ship
the Royal Mary, because he arrived there on
Christmas Day in 1643. This small island in
the Indian Ocean is so far from any other
landmass that its plants and animals are quite
unique. People did not live there earlier, so
there has been no human interference. As a
result, it is of immense interest to scientists.
An unknown continent
The early inhabitants of Australia are believed to
have come from Southeast Asia about 48,000 years ago.
Q What is the Australian climate like?
A Australia is the driest and flattest
continent inhabited by people. Most of it
is desert, arid land or hummock grasslands.
The north has a warm, tropical climate with
rainforests, mangrove swamps and grasslands.
The south-east and south-west have a cool
and temperate climate. Australia is an island
with an area of 7,686,850 square kilometres
(2,967,909 square miles), surrounded by the
Indian and Pacific Oceans. It has a coastline
of 25,760 kilometres (16,007 miles) where
nearly 90 per cent of its population lives.
Natural beauty
New Zealand (left) is known for the beauty of its
mountains and lakes. The beaches of Australia (right)
are very popular with surfers.
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Australia and Oceania
Q How long have people lived in Australia?
A Humans began to live in Australia about
48,000 years ago. They were hunter-gatherers.
Their descendants are Aborigines and Torres
Straight Islanders. There were about 350,000
Aborigines when the Europeans first landed
in 1606. Today, most Aborigines live in the
desert-like central part of Australia called the
‘outback’, having been pushed out of the
more fertile areas by the European settlers.
Q Who discovered Australia?
A The first European to find Australia
was the Dutch navigator Willem Jansz, who
sighted Cape York Peninsula in 1606. On
26 January 1788, the British established a
penal colony in New South Wales to house
convicts whom they could no longer lock up
in the overcrowded British jails. After 1864,
they stopped shipping convicts to Australia.
The Aborigines were forced off their land by
the Europeans and several died in their new
homes. Today, they make up 2.2 per cent of
the total population. Many of the 20.6 million
Australians are immigrants from Great Britain
and Ireland.
Corroboree
An Aboriginal word,
Corroboree means dance,
music and theatre.
Sports crazy
Australians are reputed
to be a nation of sports
lovers. Whether it is
cricket, Australian-style
football, tennis, swimming,
surfing or athletics, stadiums
are almost always full.
Try these too…
Earth’s Atmosphere
(26–27), Seasons and
Climate (28–29),
Mountains, Valleys and
Caves (30–31)
That’s some barrier
The Great Barrier Reef, the longest coral reef in the world,
stretches for over 2,000 kilometres (1,250 miles) in the Coral
Sea off north-eastern Australia. It is made up of 3,000 reefs and
900 islands. The Great Barrier reef is a precious environmental
site because it is home to many thousands of species of fish
and marine animals. In 1981, it was made a World Heritage
Site. However, life on the reef is still under threat from
over-fishing and pollution.
Q Why do koalas live only in Australia?
A Australia and the islands of Oceania are
ancient lands that have been isolated from
other continents for millions of years. That is
why 84 per cent of Australia’s mammals and
plants and almost half of its birds cannot be
found anywhere else in the world. These
include the koala, kangaroo, platypus,
echidna, brush-tailed possum and wombat,
and birds like the emu and the kookaburra.
Other native animals include reptiles like
crocodiles, snakes and lizards. The saltwater
crocodile of northern Australia is the largest
reptile in the world. The tuatara, the most
ancient reptile, is found in New Zealand. It
can live for up to 100 years.
115
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Continents, Countries and People
Europe
Europe is the sixth of the seven continents in terms of size.
It covers 10,390,000 square kilometres (4,010,000 square miles),
which is 2 per cent of the surface of the Earth. To the north
of Europe lies the Arctic Ocean, and to the west, the Atlantic
Ocean. To the south, Europe is separated from Africa by the
Mediterranean Sea. To the east, the boundary is not clear,
but it is around the Ural Mountains and the Caspian Sea.
Northern
Ireland
Scotland
England
Wales
British Isles
The United Kingdom is
made up four countries:
England, Scotland, Wales
and Northern Ireland.
Quick Q’s:
1. Is the Vatican City
a country?
Vatican City, which is
an enclave in Rome,
is the world’s smallest
independent country.
It is the seat of the
Roman Catholic
Church. It is ruled
by the Pope.
2. Why is Norway
called the land of
the midnight Sun?
One-third of Norway lies
north of the Arctic Circle.
From May to the end
of July, this region has
continuous daylight.
3. Where is Istanbul?
Istanbul is in north-west
Turkey. It is the only
city in the world to be
in two continents –
Europe and Asia. It
is divided in to two by
the Bosporus Strait.
116
Europe
Q What is the landscape of Europe like?
A Europe is more mountainous towards
Temperate land
The Gulf Stream that flows in from the Atlantic Ocean
keeps north-western Europe warmer than other places
at the same latitude.
the south, which also has some of the best
beaches, on the Mediterranean coast. The
Alps cover parts of Austria, Slovenia, Italy,
Switzerland, Liechtenstein, France and
Germany. Although the Alps
have high peaks like Mont
Blanc and Piz Bernina, the
highest peak in Europe is
Mount Elbrus in Russia,
5,642 metres (18,510 feet), in
the Caucasus range.
Moving beyond the Alps,
the Pyrenees and the
Carpathians, the land rolls
into the Great European
Plain. The British Isles are
separated from the rest
of the continent by the
English Channel and
the North Sea.
Q When did people start living in Europe?
A Neanderthal man reached Spain by
sailing, floating or swimming across the Strait
of Gibraltar from Africa. They disappeared
mysteriously about 30,000 years ago when
homo sapiens (modern man) began to arrive.
The first humans probably came to Europe
about 10,000 years ago. Although Europe
is relatively small, more than 710,000,000
people – about 11 per cent of the world’s
population – live here. Only Asia and Africa
have more people.
Flamenco dancer
The flamenco of Spain is one of the many
traditional dance forms popular in Europe.
City of canals
Venice, a city off the coast of north-eastern Italy,
has canals instead of roads.
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Europe
Q What languages are spoken in Europe?
A As many as 41 languages are spoken
in different parts of Europe. Some of the
languages, such as English, French, Spanish,
German and Russian, are spoken by millions
of people in many countries all over the world.
One Europe
Europe has about 47 countries, some
of which, like Liechtenstein, are among
the smallest in the world. Of these 47
countries, 27 are part of the European
Union (EU). The EU is the largest political
and economic group in the world. It has its
own currency called the euro.
Q Does Europe have forests?
A Centuries ago, about 90 per cent of
Europe was covered in forest. Now, more than
half of this has been felled. However, in
countries like Finland, 72 per cent of the land
is still covered by forests. Evergreen and
deciduous forests cover most ground. Conifer
forests are found in Scandinavia and parts of
Russia and Ukraine. Further north is the taiga
region with forests of spruce, birch and pine.
The Mediterranean region has cork oak
forests, cypress trees and olives.
Q Are the forests full of animals?
A Europe’s forests are home to brown
bears and wolves, which are now protected
by law. Smaller animals include lynx, badgers,
hedgehogs, wildcats, jackals and foxes. Snakes
like the viper and birds like the vulture, eagle
and owl are also found here. The northern
parts of Scandinavia have herds of reindeer,
some of whom have been domesticated for
centuries. The forests of Scotland are famous
for the red deer. Europe is home to many
bird species that spend their winters in
warmer Africa, and return to their
European homes
every spring.
Wild cat
The lynx is the largest wild cat found in Europe. Apart
from the bear, it is the prime predator in the forests of
the continent.
Traditional food
Steak (left) and Yorkshire
pudding (above) are
among the traditional
foods of Europe.
Switzerland is famous
for its dairy products,
especially cheese.
The cuisines of all
countries on the
Mediterranean coast are
famous around the world.
Try these too…
Earth’s Atmosphere
(26–27), Seasons and
Climate (28–29),
Mountains, Valleys and
Caves (30–31), Oceans
(34–35), Volcanoes
(36–37), Ancient Greece
(128–129), Ancient
Rome (130–131),
Medieval Europe
(136–137), The
Renaissance (142–143)
Prickly spines
The little hedgehog with its
prickly spines is common
but shy, nocturnal and
tough to spot.
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Continents, Countries and People
Africa
Africa is the second largest continent in the world. The
Romans named it ‘Africa terra’, which means land of the
Afri, after a tribe who lived in North Africa. Africa has around
840,000,000 people. It covers about 30,300,000 square
kilometres (11,700,000 square miles) including the islands.
This is roughly 6 per cent of the total surface of the Earth.
Quick Q’s:
1. Which is the highest
point in Africa?
Kibo on Mount
Kilimanjaro is the
highest peak. It is 5,895
metres (19,341 feet)
tall. Although close to
the equator, the peak is
so high it is covered
with snow.
2. Does Africa have any
big lakes?
Lakes Victoria,
Tanganyika, Albert,
Edward and Kivu are
the Great Lakes of
Africa, in the Great Rift
Valley. Lake Victoria
covers 69,500 square
kilometres (26,836
square miles) and is
the world’s second
largest freshwater lake.
3. Does Africa have
major rivers?
The Nile River, at 6,825
kilometres (4,241 miles)
long, is the longest
river in the world.
Other rivers in Africa
include the Congo, the
Zambezi and the Niger.
4. Is the Sahara the
only desert in Africa?
Three major deserts
cover one quarter of
Africa. The Sahara
covers 11 countries.
The Kalahari desert
and the Namib desert
are in the south.
118
Africa
Q Where can I find Africa on the globe?
A Africa is the only continent straddling
the tropic of Cancer, the equator and the
tropic of Capricorn. It lies to the south of
Europe and the Mediterranean Sea and to
the west of Asia, beyond the Red Sea. To its
west is the Atlantic Ocean and to its east is
the Indian Ocean. It is a long continent,
stretching 8,000 kilometres (5,000 miles)
from the tip of Tunisia in the north to its
most southern point in South Africa, the
Cape of Good Hope. It is widest at the centre,
with 7,400 kilometres (4,600 miles) between
its most eastern point in Somalia and its
western coast. Africa’s coastline is 26,000
kilometres (16,100 miles) long.
Q How many countries are there in Africa?
A Africa is home to 54 countries. The largest
is Sudan and the smallest is the Seychelles, a
cluster of islands to its east. Of all the islands,
Madagascar is the largest, covering 587,000
square kilometres (226,658 square miles).
Tribal dance
Different tribes in Africa have different traditional
dance forms. This is a dance in Nigeria, western Africa.
Many climates
Africa has several different climate zones. The Sahara
keeps the north hot and dry. The centre has the
rainforests, the south-east the savannah.
Q How long have humans lived in Africa?
A The first human life on Earth started in
Africa more than 7 million years ago. Our
ape-like ancestors lived there. The ‘cradle of
humankind’, a series of limestone caves near
Johannesburg in South Africa, is the oldest
sign of human civilization that we know of.
People who live north of the Sahara desert
are called North Africans and people who live
south of the Sahara are called sub-Saharan
Africans. One of the earliest tribes, the
Berbers, were pushed into the Sahara and the
Sahel (the area bordering the Sahara) in the
seventh century by the Arabs, who settled on
the northern coast. Other tribes still found in
sub-Saharan Africa include the Bushmen of
the Kalahari Desert, the Masai of Kenya, the
Twa pygmies and the Tutsi of west and central
Africa. Europeans, people from the Middle
East and Asians have also settled in Africa,
where they colonized several countries. In the
last century, most European countries handed
these colonies back to the local people. There
are now people from all over the world who
live in Africa.
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Africa
Q Is there poverty in Africa?
A Africa is the world’s poorest continent.
Of the 175 countries ranked in the 2003
United Nations Human Development Report,
25 African countries ranked lowest. Sixty per
cent of the people depend on agriculture,
and they have been getting less and less
money by exporting their crops. The situation
has been worsened by poor rainfall since the
1980s in many countries south of the Sahara.
What-a-fall!
Victoria Falls, locally called Mosi-oa-Tunya (meaning ‘smoke
that thunders’), is on the Zambezi River between Zambia and
Zimbabwe. The falls are about 1.7 kilometres (1 mile) wide and
128 metres (420 feet) high – the largest single sheet of water in
the world. In 1855, David Livingstone named the falls after
Queen Victoria. They are a World Heritage Site.
Q What plants and animals might I see on
an African safari?
A Cypress, pine, oak, orange and olive trees
grow along the Mediterranean coast of North
Africa. The date palm is the common plant in
the Sahara oases. Rainforests in north-west
and central Africa have hundreds of species
of plants and animals, including elephants,
gorillas, snakes, okapi and crocodiles. The
baobab and the acacia are common trees
in the mixture of grassland, desert and
mountains that cover much of eastern and
southern Africa. This is home to the lion,
elephant, cheetah, rhino, zebra and many
kinds of monkeys, apes, deer and antelope.
Haven for animals
The African savannah – now a series of national parks
– is home to a huge variety of wild animals.
Try these too…
Earth’s Atmosphere
(26–27), Seasons and
Climate (28–29),
Mountains, Valleys and
Caves (30–31), Other
Landforms (32–33),
Oceans (34–35),
Volcanoes (36–37)
Traditional decoration
A woman of the Himba
tribe in Namibia, southwestern Africa, wears a
traditional headdress and
jewellery. The decorations
have cultural
significance.
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Continents, Countries and People
Asia
Asia is the largest continent in the world. It spreads over an area
of 44,390,000 square kilometres (17,139,000 square miles). This
is 8.7 per cent of the total area on Earth, or 29.8 per cent of the
total landmass. Over 3.5 billion – six out of every ten – people
live in Asia, in some of the most populated countries in the
world like China and India. Except for a few of its islands, Asia
is in the northern hemisphere – north of the equator.
Quick Q’s:
1. Which are Asia’s
largest cities?
Seoul, Mumbai, Jakarta,
Tokyo and Shanghai
are some of the largest
cities, not only in Asia,
but in the world!
2. What languages are
spoken in Asia?
There are more
languages spoken in
Asia than on any other
continent – over 100 in
the Philippines and
more than 500 in
Indonesia alone.
Chinese, Hindi, Arabic
and Bengali are among
the languages spoken
by over 100 million
people. Chinese will
soon be spoken by
more people than any
other language.
People in most Asian
countries speak more
than one language.
3. What are the most
famous architectural
structures in Asia?
There are old cities,
forts and monuments
all over Asia. The Great
Wall of China is the
only man-made
structure that can be
seen from the moon!
The Taj Mahal in India
and the Angkor Wat
in Cambodia are
among the world’s
famous monuments.
120
Asia
Q Who are Asia’s neighbours?
A To its west, Asia borders Europe. If
you drew an imaginary line along the Ural
mountains to the Caspian Sea, the Black Sea
and the Aegean Sea, it would be the western
border of Asia. Asia has the Arctic Ocean in
the north, the Indian Ocean in the south,
and the Pacific Ocean in the east.
Q What is the landscape of Asia like?
A Asia is home to Mount Everest, the
highest point on Earth and to the Dead Sea,
the lowest surface on Earth. Along the coast
and in river valleys are fertile plains.
Modern cities
Many Asian cities such as Dubai
(seen here), Tokyo, Shanghai,
Hong Kong and Singapore are
full of high rise buildings.
Large and populous
The continent of Asia accommodates about 60 per cent
of the world’s total population.
They include the valleys of the Yangtze
and Hwang Ho rivers in China; the Ganges,
Brahmaputra and the Indus rivers in south
Asia; and the Tigris and Euphrates rivers in
west Asia. The Yangtze is the longest river in
Asia, covering 6,380 kilometres (3,964 miles).
The highest mountain ranges in the world are
in Asia – the Himalayas, Hindu Kush, Kunlun
and Tien Shan mountains.
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Asia
Q What kind of plants grow in Asia?
A Asia is so large, it contains various
biomes (climate areas with similar plants and
wildlife). In the northern sub-polar regions,
grasses and moss grow. Away from the coast,
the coniferous forests form the taiga. Central
Asia has vast grasslands known as the steppe.
South-west Asia is arid and desert-like. Further
south and east, in countries such as India,
Sri Lanka, Malaysia and Indonesia, tropical
rainforests abound.
Sitting on a seabed
During the Paleozoic and Mesozoic eras, 570 million to 65 million
years ago, the Tethys Sea covered most of what is Asia and parts
of Europe. The Indian subcontinent broke off from Africa and
drifted towards the north-east. As the land pushed north, it
crumpled and folded to form the Himalaya mountains. Gradually,
the islands of eastern Asia, such as Japan and Taiwan, began to
grow. The plates that make up Asia are still moving and settling,
which makes this region prone to volcanic activity, earthquakes
and natural disasters such as the 2004 tsunami that devastated
many countries around the Indian Ocean.
Q Do people live all over Asia?
A Most people live along the
river valleys and grow crops like
rice and wheat. Many others work
in mines, since Asia is rich in
petroleum, iron and bauxite.
Asia is the world’s largest producer
of bananas, cotton and
tea. With such a long coastline,
fishing is also an important
source of income. In
China and India, where
industry is booming,
many people are moving
away from rural areas to
live in densely
populated cities.
Q Does Asia
have a lot of
wildlife?
Try these too…
Earth’s Atmosphere
(26–27), Seasons and
Climate (28–29),
Mountains, Valleys and
Caves (30–31), Other
Landforms (32–33)
International tastes
The cuisines of China,
India and Japan are
famous all over the world.
Tradition of dance
Many countries in Asia
have a well-developed
tradition of dance, music
and literature.
Tea ceremony
Asian countries like
Japan have very formal
traditions like that of
the tea ceremony.
A There are
some animals
in Asia that
are not found anywhere
else in the world. The giant
panda of China, the orangutan
of Borneo and Sumatra and the komodo
dragon of Indonesia are all unique
to the continent. The tiger, the Asiatic lion and
the rhino are all under threat of extinction.
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Continents, Countries and People
The Poles – The Arctic and Antarctica
The North and South Poles are at the two ends of the Earth’s
axis. The North Pole is the northernmost part of the Earth,
and the most southern tip of the Earth is the South Pole, in
Antarctica. The Arctic and the Antarctic are the most arid (dry)
places on Earth.
Antarctica
Quick Q’s:
1. Why is 21 June an
important day around
the Arctic Circle?
On 21 June or the
summer solstice, the
Sun does not set north
of the Arctic Circle.
That is why this area is
called the land of the
midnight sun. For the
local residents, this is a
time to celebrate. On
the other hand, on 21
December – the winter
solstice – the Sun does
not rise at all.
2. What lies below the
ice and snow?
Many minerals have
been found in the
Arctic, although mining
is difficult. Russia and
the US have found
deposits of coal, copper,
nickel, gold, uranium,
tungsten, diamonds,
natural gas and oil.
Antarctica may also be
rich in minerals.
3. Do people live in the
Arctic?
Hunters from Siberia
were the first people
to live in the Arctic,
arriving about 5,000
years ago. The Inuit of
North America, the
Greenlanders, the
Lapps of western
Europe, and some
groups of people in
Russia and Siberia live
in the Arctic. They
hunt, fish and keep
herds of reindeer.
122
Q What is the Arctic?
A From the air, the Arctic would look like
a blob of ice surrounded by ocean and rock,
with a scattering of islands. The Arctic Circle
is an imaginary line around the Earth which
represents the southern limit of the Arctic
region. The average summer temperature
north of the Arctic Circle does not rise above
10 °C (50 °F).
Q Which countries are in the Arctic?
A Parts of Canada, Alaska (the largest
state in the USA), Russia, Norway, Sweden,
Finland, Iceland and Greenland lie within
the Arctic circle. The Arctic landmass is made
up of mountains, plateaus and tundra plains.
The tundra is flat and marshy and covered by
permafrost (permanent ground frost). The
sea in the Arctic, known as the Arctic Ocean,
is frozen over for much of the year.
Continent of ice
Huge cliffs of ice are found at the edge
of the Antarctic continent.
Discovering the south pole
For centuries, people kept searching for the ‘Southern
Continent’. Antarctica was finally discovered in 1819.
Q Does it rain in the Arctic?
A The climate in the Arctic is polar. It has
a short, cool summer and long, freezing
winter. In the outer edges of the Arctic – the
tundra – the average summer temperature is
between 0 and 10 °C (32–50 °F). Among the
ice caps, it is below 0 °C (32 °F) throughout
the year, and there is a permanent cover of
snow. Most of the precipitation (rainfall) is
frozen and falls as snow, but it does
occasionally rain.
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The Poles – The Arctic and Antarctica
Q Who lives in Antarctica?
A Antarctica has no local population.
It is the least populated continent. In 1819
William Smith discovered a landmass which
he called the South Shetland Islands. He
believed it to be a group of islands, but in
1840 it was declared a continent.
Q Are the polar ice caps melting?
A Polar ice caps have been melting at an
increasing rate since the 1990s due to the
increasing level of greenhouse gases like
carbon dioxide in the Earth’s atmosphere. In
2005, 221 cubic kilometres (53 cubic miles)
of the Greenland ice cap melted and fell into
the sea, compared to 92 cubic kilometres
(22 cubic miles) in 1996. One cubic kilometre
is three times the amount of water used in a
large city in a year. This water is raising sea
levels, threatening coasts all over the world.
Icebreaker
Many ships have been surrounded and immobilized by ice
in Arctic and Antarctic seas in the past. Modern ships that
sail in these waters are specially built to ram their way
through thick sheets of ice.
Maximum distance
Every year, the Arctic tern
migrates from the Arctic
to Antarctica and back!
This is the longest regular
migration by any animal
that we know about. For
its effort, the Arctic tern
does get to enjoy two
summers every year.
Hole in the ice
The Arctic ringed seal is
the only seal that can
make a breathing hole
in ice and live under it
throughout the year.
Try these too…
Earth’s Atmosphere
(26–27), Seasons and
Climate (28–29),
Mountains, Valleys and
Caves (30–31), Other
Landforms (32–33)
Night light
The aurora is a coloured glow seen in polar regions at night. In
the Arctic, it is called the aurora borealis or northern lights, and
in the Antarctic, the aurora australis, or southern lights. These
colourful lights are caused by magnetic fields, when high-energy
particles from the Sun react with atmospheric gases.
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World History
Ancient Mesopotamia
A large part of ancient Mesopotamia is now covered by the
country of Iraq. The fertile land near the Euphrates and Tigris
rivers is known as the ‘Cradle of Civilization’, and it was here
that the first ever Mesopotamian civilizations were born.
Mesopotamia was home to the ancient cultures of the
Sumerians, Akkadians, Babylonians and Assyrians.
Location of the ancient
civilizations in Egypt and
Mesopotamia.
Watering the land
Mesopotamians were very clever. They built elaborate
canals and dams to irrigate their dry farm lands.
Q What did the Mesopotamians do
for a living?
A
Symbols of the past
The cuneiform is the
oldest script in the world.
Quick Q’s:
1. Which was the oldest
Mesopotamian
civilization?
The Sumerians settled
in Mesopotamia about
4000 BC, making them
the first civilization in
the world.
2. Who ruled
Mesopotamia?
Every Mesopotamian
city was ruled by a
king, who was thought
to have been chosen
by the god of the city.
3. Were there wars in
ancient Mesopotamia?
Mesopotamians fought
with each other over
land, water and power.
The first ever war
probably took place
between the cities of
Lagash and Umma.
124
A large part of the Mesopotamian society
consisted of farmers. The Sumerians were the
world’s first farmers. They cultivated a variety
of crops including wheat, barley and flax. The
climate in Mesopotamia was dry, so the
people living there had to depend on the
rivers for irrigation. They built canals to carry
water from the rivers into large reservoirs,
where it was stored. The farmers also built
dykes to protect their houses from floods.
Q Why did the Mesopotamians build boats?
A Apart from farming, Mesopotamians
also traded in goods like stone and metal.
They realized that these materials could be
transported easily along the rivers and across
the sea using boats. So the Mesopotamians
built different types of boats. They had
wooden boats with triangular sails, a wooden
raft called a kalakku, and a tub-like boat made
of reeds and covered with animal skin known
as a guffa.
Down the river
Boats were used for transport and trading goods in
ancient Mesopotamia.
Q Were the Mesopotamians really the first
people to develop writing?
Q What is a ziggurat?
A The Mesopotamians believed that their
cities and towns were protected by gods.
They built temples to these gods on top of
large, pyramid-like structures called ziggurats.
These were made of mud bricks and had
between three and seven storeys. The ziggurat
was often built at the centre of the city.
A
The Sumerians were the first to develop
a written language. Their script is known as
cuneiform and was composed of a series of
symbols. These were carved on to clay tablets
using a reed called a stylus. They used the
tablets to keep records of trade and land
ownership. There were some religious texts
too. The Sumerian script was adapted by the
later civilizations including the Akkadians.
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Ancient Egypt
Ancient Egypt
The civilization of ancient Egypt on the banks of the Nile lasted
for more than 3,000 years and was the longest continuous
civilization in the world. During this period there were many
political and economic changes, but the basic culture, religion
and lifestyle remained the same throughout.
Q Why is the Nile River known as the
Deciphering sacred carvings
lifeline of Egypt?
The ancient Egyptians used a form of
writing that was made up of pictures.
This was known as hieroglyphics. The
word hieroglyphic means sacred carving
in Greek. For years, no one could read
these strange-looking symbols. Then in
1799, the famous Rosetta Stone was
discovered at Rashid (Rosetta), in Egypt.
This stone contains an order issued by
the priests of Ptolemy V in 196 BC. The
order is written in a mixture of Egyptian
hieroglyphics, Greek and other ancient
scripts. With the help of the Greek texts,
experts were soon able to decipher the
hieroglyphic script.
A It was the fertile banks of the Nile that
attracted early settlers to Egypt. These settlers
formed two different kingdoms – Upper
Egypt in the south, and Lower Egypt in the
north, with the Nile Delta. People fished in
the Nile and farmed on its banks.
Q Why did ancient Egyptians
build pyramids?
A Ancient Egyptians built pyramids as
a final resting place for their kings, called
pharaohs. They believed that their pharaohs
continued to look after the affairs of the
kingdom even after death. It was therefore
necessary to make their souls comfortable.
The Great Pyramid of Khufu, made out of
stone, is the grandest of all pyramids. This
amazing monument is over 146 metres
(480 feet) tall and has survived for more
than 4,000 years!
Q What is a mummy?
A The ancient Egyptians believed in life
after death. They thought that each person
had three souls – ka, ba and akh. It was said
that the body had to remain intact even
after death for akh to exist happily. So, the
ancient Egyptians preserved dead bodies by
a process called embalming. The process was
known only to some priests. The embalmed
body is called a mummy, and some have
survived until today!
Massive effort
Many people were needed
to build a pyramid.
Comfortable afterlife
Ancient Egyptians buried
food, furniture, jewellery
and everything else that
was thought necessary for
the afterlife along with
the mummies. It was
believed that the dead
had to be well-provided
for if they were to
perform their duties
effectively after death.
Try these too…
Africa (118-119),
Discovery of New Lands
(144-145), Architecture
(164-165), Art and
Artists (166-167), World
Religions (176-177)
125
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World History
Ancient India
and China
Most ancient civilizations developed in river valleys. The Indus
Valley civilization, from 3000 to 1500 BC, covered Afghanistan,
Pakistan and western India. The Chinese civilization developed
along the banks of the Hwang-ho River in about 2100 BC and
was governed by various dynasties, or ruling families.
Quick Q’s:
1. What is
Mohenjo-Daro?
Mohenjo-Daro was the
largest city in the Indus
Valley and means
mound of the dead. It
had been abandoned
for many centuries.
Then in 1924, while
a railway line was
under construction,
workers started digging
near the mound. When
archaeologists saw the
ancient bricks the
workers were digging
up, they realized they
had hit upon an
important ancient site.
2. Who was Empress Xi
Ling-Shi?
Empress Xi Ling-Shi is
said to have discovered
silk when a cocoon fell
into her cup of tea and
the silk unravelled. By
3000 BC, silk was worn
by Chinese royalty.
126
Chinese
civilization
Q
What did the people of the Indus Valley
do for a living and for recreation?
Q
Unknown script
A seal of the Indus Valley
civilization, with its
unknown script.
Indus Valley
civilization
What was special about the ancient Indus
Valley civilization?
A Farmers grew barley, peas, melons, wheat,
A The Indus Valley civilization grew up
cotton and dates and herdsmen kept sheep,
pigs, cows and water buffalo. Fishermen caught
fish using hooks like modern fishermen do
today. Grain was stored in a large town granary.
Specialized writers kept records of trade and
land ownership on the terracota seals. The
people were expert artists and potters, and
could weave. They could work metal to make
jewellery, statuettes and weapons. There were
market days every week, to which people came
from far away. Colourful clothes and jewellery
were sold in the markets. The women wore
lipstick made out of vegetable dyes. The men
went hunting, sometimes with falcons.
Children played with different toys like small
carts, whistles shaped like birds, and monkeys
that slid down a string.
around 3000 BC along the banks of the Indus
and Ghaggar-Hakra rivers. Before this, people
generally lived in the forest or in small
villages. When the civilization developed,
great cities were built, with populations of
up to 35,000 people. These cities were very
advanced and carefully planned with straight
roads. The people knew how to make baked
bricks out of mud and they built homes two
storeys high. Each home had a well and
a bathroom from which waste drained in to
sewers through clay pipes, some of which
were covered and were high enough for a
man to walk through. The sewers drained
in to a river or the sea.
Ancient priest
Scholars think
this is the statue
of a priest from
the time of the
Indus Valley
civilization.
Swimming pool or religious bath?
The great bath of Mohenjo-Daro may have been used for
ritual bathing before prayers. But some scholars think it
was also used for recreation.
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Ancient India and China
Q What are the early Chinese dynasties
Teatime
known for?
The ancient Chinese knew all about tea. Tea, which they called
tu, was grown in China from at least 1000 BC. It was often used
in religious ceremonies. For a long time, the leaves were eaten
like vegetables. Gradually, from the time of the
Western Han dynasty around 207 BC,
people began to use tea as a
medicine and as a royal drink.
But it wasn’t until the Tang
dynasty that began in 618 AD
that drinking tea became an
important part of Chinese life.
A
The Xia dynasty is the earliest known
Chinese dynasty (2100–1600 BC). It lasted for
about fourteen generations. During the
Shang dynasty (1600–1027 BC), a written
language began to take shape and history
started to be recorded. At this time, people
also learnt to make things out of bronze.
River valley
An aerial view of part of
the Yangtze river and its
valley, where the ancient
Chinese civilization was
developed over many
centuries.
The Shang dynasty in China was followed
by the Zhou dynasty (1027–221 BC), when the
Chinese learnt to use iron. The rulers during
this period encouraged their people to grow
crops, spin silk, make pottery, build boats and
carts, and hunt with bows and arrows. In 221
BC, Emperor Qin Shi Huang became the first
king to rule over the whole of China. He
made sure that all Chinese people spoke the
Qin language. A written language with over
3,000 characters was developed.
Destroying knowledge
Emperor Qin Shi Huang
ordered the burning of
most books in the country
in 213 BC, destroying very
valuable information about
ancient China. He believed
that those who wrote
books were spreading
dissent against him.
Try these too…
Asia (120–121),
Discovery of New Lands
(144–145), Architecture
(164–165), Art and
Artists (166–167), World
Religions (176–177)
Q Who was Confucius?
A Confucius was born in 551
BC during
the rule of the Eastern Zhou dynasty. He was
a teacher and a philosopher. He travelled
widely, giving advice to different rulers and
trying to convince them to be more caring
towards their people. He believed in the
family and in peace, truth and cooperation.
He also believed that the king should be
just and fair. The years of Confucius are
known as the Golden Age of Chinese
philosophy. His teachings were followed
by generations of rulers and officials who
governed China.
127
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World History
Ancient Greece
The ancient Greek civilization is the oldest in the western
world. This civilization thrived about 3,000 years ago. One
of the earliest cultures to flourish in the Greek islands was
the Minoan civilization on the island of Crete, which began
around 2700 BC. The ancient Greek civilization we know
today emerged around 800 BC.
Quick Q’s:
1. Did ancient Greeks
know about democracy?
Democracy – a form of
government elected
by the citizens of a
country – was first
introduced in Athens.
2. Who was Homer?
Homer is one of the
best-known Greek
writers. He wrote the
two famous epic
poems – The Iliad
and The Odyssey.
3. What is the
Parthenon?
The Parthenon is the
most famous building of
ancient Greece. It was a
temple to Athena, the
Greek goddess of war
and wisdom. The
Parthenon has been
renovated many times.
The latest round started
in 1975, and has been
going on since then.
4. Did ancient Greeks
make pottery?
Ancient Greeks made
pottery for their daily
use. Some of the most
commonly used vessels
included amphora
(wine jars), hydria
(water jars) and
krater (mixing bowls).
These vessels were
often painted with
beautiful scenes from
famous Greek legends.
128
Location of the ancient
Greek civilization.
Q What are city-states?
A Ancient Greece was divided into many
small, self-governing communities. This was
largely because of the geography of Greece,
where every island and many cities are cut off
from their neighbours by mountain ranges or
sea. These smaller independent communities
formed what were known as city-states. Each
city-state had its own customs and laws. The
most important city-states were Athens,
Sparta, Corinth and Thebes.
Q What caused the Peloponnesian war?
A Around the fifth century , the Athenians
BC
became very powerful. They began to dominate
all the other city-states, especially in war.
Pottery class
Ancient Greeks had a system of training in all the arts.
The city of Sparta became jealous and,
supported by Corinth, went to war against
Athens in 431 BC. The Peloponnesian War
lasted for 27 years. Athens was defeated. It
was stripped of its navy and lost its colonies.
Q Were ancient Greeks good at art?
A The Statue of Zeus at Olympia by Phidias
was one of the seven wonders of the ancient
world. The statues made in ancient Greece
showed detailed knowledge of the human
anatomy. Ancient Greek architecture
consisted mainly of temples. They had simple
square or rectangular shapes, surrounded by
tall columns. Greek art has had enormous
influence on the cultures of many countries.
War
The ancient Greeks were well-known for the many wars
they fought on land and sea. City-states fought one
another, then united to fight Persian invaders.
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Ancient Greece
Q What did the ancient Greeks do for fun?
A Ancient Greeks enjoyed watching plays.
Ancient Olympics
A discus thrower takes
part in a competition in
ancient Greece.
Almost every city had open-air theatres where
drama festivals took place. Awards were given
to the best playwright. Greek tragedy and
comedy have had a lasting impact on western
drama and culture.
Q When were the first Olympic Games held?
A The ancient Greeks were keen
sportsmen. The Olympic Games were an
athletic and religious celebration held in
the town of Olympia. The first Olympic
Games were held in 776 BC, in an attempt
to bring all the city-states together in friendly
competition.
Try these too…
Europe (116–117), The
Renaissance (142–143),
Architecture (164–165),
Art and Artists
(166–167), Theatre
(170–171), World
of Sports (172–173)
Q Did girls in ancient Greece go to school?
A Only boys went to school in ancient
Greece. Girls were not sent to school. They
were taught housework and married by the
age of 13. Women were not allowed to go out
to work, or even to vote. Only men took part
in the affairs of the state.
Birth of democracy
In the city-states of ancient
Greece, men openly debated
and voted on many issues.
Living in slavery
Slaves in ancient Greece had no rights at all – they didn’t even
have their own names! They used the names their masters gave
them. People became slaves in many ways; some were children of
slaves, some were abandoned as infants; some were children sold
by their families for money. Prisoners of war also became slaves.
129
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World History
Ancient Rome
The ancient Roman civilization was the most powerful of all
ancient civilizations. In the beginning Rome was a small city-state
that was under the control of the Etruscans. It soon grew to
become the largest empire in the ancient world. Ancient Rome
was greatly influenced by the ancient Greek culture.
Quick Q’s:
1. What was special
about the Colosseum?
The Colosseum is a
huge open-air theatre
in Rome. It was built by
Emperor Vespasian and
his sons. It held 50,000
people. Gladiatorial
games and mock naval
battles were the main
events held in it.
2. Did all ancient
Romans wear togas?
A toga was a long piece
of cloth worn by men
in ancient Rome. It was
usually draped over the
tunic. The toga was a
symbol of the person’s
position in society.
Therefore, slaves and
most poor men did not
wear togas.
3. What are insulae?
The poor people in
ancient Rome lived
in small, crowded
apartments known
as insulae. These
apartments had only
2–3 rooms, and large
families lived in them.
4. Who were the
bestiarii?
Sometimes, criminals
who had been
sentenced to death and
prisoners of war were
forced to fight wild
animals with their bare
hands in the Roman
arena. They were
called bestiarii.
130
Location of the ancient
Roman civilization.
Q When was Rome founded?
A According to legend, Rome was founded
on 21 April 753 BC by Romulus and Remus,
who were twins born to Mars, the Roman
god of war. A fight broke out between the
two brothers regarding the exact
location of the city of Rome, and
Romulus ended up killing
Remus. Romulus then completed
building the city that was later
named Rome after him.
Q
Was ancient Rome
ruled by kings?
A Romulus was the first
of the Seven Kings of Rome
to rule the city. Around
509 BC, Tarquin, the last of
the Seven Kings, was made
to step down from the
throne and the Roman
Republic was established.
Under this system, Rome
was ruled by magistrates
and other representatives
who were elected by the
people. The Republic of
Rome dominated all of
western Europe. However, by
30 BC, Rome once again came
under the rule of kings and
became known as the Roman
Empire. The Roman Empire
was later divided into
two parts – eastern
and western.
Roman soldiers
Roman soldiers were the best trained,
the most disciplined and the most
feared in the ancient world.
Q Who were the Five
Good Emperors?
A The Five Good Emperors
ruled ancient Rome between
AD 96 and 180. They were
Nerva, Trajan, Hadrian,
Antoninus Pius and Marcus
Aurelius. The Five Good
Emperors were so-called
because ancient Rome
prospered the most under
them. They were known for
their fair policies and good rule.
Army officer
An army officer was an important citizen in Rome,
especially during the time the Roman Empire was
expanding. They held titles that showed the
number of soldiers they commanded. For example,
a centurion commanded a hundred soldiers.
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Ancient Rome
Q Were the ancient Romans good
at engineering?
A Ancient Romans were brilliant architects
and engineers who constructed magnificent
buildings throughout the Empire. However,
they are best known for their amazing public
baths, roads, aqueducts and drainage systems.
Baths were a very important part of life in
ancient Rome. Both men and women visited
the baths at least once a day. The water in the
baths was channelled through aqueducts.
Q What did ancient Romans do
for recreation?
A Ancient Romans loved dance and music.
The rich held elaborate feasts in which they
served exotic food like oysters, pork and
snails and entertained their guests. All the
people were very fond of gladiatorial games.
Roman bath
The Roman bath had many rooms, with water at various
temperatures and facilities for exercise.
Q Why did ancient Romans
build aqueducts?
A The Romans built aqueducts to
carry water to the cities. Sometimes,
the water would be carried from
rivers or streams as far as
95 kilometres (59 miles) away!
They used natural gravity to
carry the water over such long
distances. Wherever there was
a depression, walls or arches
were built over it to keep
the water flowing. The
water was stored in a large
tank, or castellum, in the city,
from where it was
distributed to public
fountains and baths.
The scribe
The scribe was an
important part of ancient
Rome. He wrote down all
the laws and the debates
in the senate.
Roman banquet
Roman banquets went on
for hours.
Try these too…
Europe (116–117),
Architecture (164–165),
World of Sports
(172–173)
Paving the way
Apart from baths and aqueducts, ancient
Romans also built roads, some of which
still exist today. Roads in ancient Rome
had multiple layers. The bottom layer,
called pavimentum, was made of mortar.
This was covered with a layer of stones
and cement. A layer of concrete and slabs
of stone was added to this. Finally, the
upper layer of concrete and smooth
pebbles was laid. This method of
building roads is known as paving.
131
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World History
Ancient Americas
Middle America, also called Mesoamerica, is the region that
stretches from central Mexico to northern Honduras. In ancient
times, it was home to some highly developed civilizations like
the Maya and the Olmec. These civilizations prospered until
the arrival of the European settlers in the sixteenth century.
Quick Q’s:
1. What type of gods
did Mesoamericans
believe in?
Ancient Mesoamerican
gods were part human
and part animal. They
represented natural
elements like the Sun
and the Moon, rain,
lightning and the
various planets.
2. Who discovered the
cocoa that we all love?
The Maya loved to
drink hot cocoa. They
believed cocoa was a
gift from their snake
god Quetzalcoatl and
that it could cure them
of illness. Chocolate is
made from cocoa.
3. Why did the
Mesoamericans bury
jewellery with
their dead?
The Mesoamericans
believed in life after
death. They buried
their dead with
jewellery, vases and toys
they thought were
needed in the afterlife.
The Mayans believed
that ordinary people
went to the underworld
when dead, but when
kings died, they went
to heaven and were
reborn as kings in
another world. When
rich people died, they
were buried under
their own homes,
while kings had
elaborate tombs.
132
Q
How did the various civilizations in
Mesoamerica develop?
A Farming in Mesoamerica goes back to
5000 BC. Various tribes knew each other and
traded in food, animal skins and jewellery.
Sometimes their armies raided each other’s
villages. Gradually, large cities with big palaces,
temples and flat-roofed pyramids were built
for the rich. The rulers were also the priests.
The workers grew crops, built houses for the
rich and fought as soldiers.
Location of Mesoamerica.
Q Who were the Olmec?
A The Olmec were the first group of
people to arrive and settle in Central
America. They made the area their home by
1200 BC. They had a calendar and calculated
time by studying the stars and a written
language which they engraved on stone. Later
civilizations learnt many things from them,
such as how to build houses. This is why they
are the mother culture of Mesoamerica.
Q
Besides farming, what were the other
kinds of work in Mesoamerica?
A People wove cloth and made rope,
baskets and fishing nets. Traders took their
wares to other villages. Huge temples,
pyramids and tombs were built. Artisans
carved and painted designs on their walls.
Stepped pyramid
The huge stepped pyramid
built by the Maya at
Chichen Itza (Mexico).
Big heads
Enormous statues of helmeted heads are the best-known
examples of Olmec art. Some were 3 metres (10 feet) tall.
Q Why are the Maya special?
A The Maya took the study of
astronomy and mathematics much
further than the Olmecs had done.
They built huge observatories
to study stars. They were
excellent artists and built
grand structures like
palaces and ceremonial
platforms. They made
tools and weapons
from volcanic glass.
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Native Americans
Native Americans
People have lived in North America for more than 12,500 years,
since before the end of the last Ice Age. Scholars believe that
these people moved from Asia to America through the Bering
Land Bridge during the last Ice Age.
Q Where did these people come from?
A Most people believe that the early
Americans crossed the Bering Land Bridge
from central Asia. This bridge now lies
underwater. Gradually people spread out
across North America. The people of
different regions developed different
ways of life.
Q Who were the Mississippians?
A The Mississippians were hunter-gatherers
who lived in the south-eastern part of what is
now the United States. They began to grow
crops about 5,000 years ago. About 2,400
years ago, they learnt how to grow maize
crops. They also grew beans, squash and
sunflowers. They buried their dead under
huge mounds. They knew how to bake
pottery and they built four-walled homes of
clay and thatch. Some of them lived in a city
called Cahokia.
Warrior
Native American warriors often dressed to look like the
animals with which they felt a spiritual bond.
Migration
routes of Native
Americans.
Q Did people live in other
parts of North America?
A
The Delaware, Mohegans,
Mohawks and Abenaki lived in the
north-east of America. They were
good hunters and used spears, bows
and arrows and clubs. They fished
with spears, hooks and nets and
lit flares to attract fish to the
surface. They knew how to
make two types of homes –
the longhouse covered
with bark, and the
wigwam covered with
reeds and animal skins.
Try these too…
North America
(110–111), Incas and
Aztecs (141), Discovery
of New Lands (144–145)
Classic teepee
Native Americans in the
Great Plains designed
a wigwam that
could be put up
and dismantled
very quickly.
The story of Hiawatha
The Iroquois people were constantly fighting among themselves.
After the death of his family a heartbroken chief, Hiawatha, was
wandering in the forest when he met the Peacemaker, who helped
him to overcome his grief. The Peacemaker took Hiawatha and
visited all the Iroquois tribes and convinced them to live in peace.
The tribes got together to form the Iroquois Confederacy. This
Confederacy continues and is one of the oldest political groups in
North America, far older than the government of the United States.
133
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World History
Q Who were the Apache Indians?
A The deserts of what is now the
God of fertility
Kokopelli is a fertility god
who was worshipped by
Native Americans in the
south-western part of the
United States.
Quick Q’s:
1. Why are Native
Americans also called
American Indians?
Columbus believed he
had landed in India
when he reached
America. He called the
locals Indians.
south-western United States were occupied by
nomadic hunter-gatherers and farmers. The
people who lived here included the Apache
and Navajo. The farmers grew maize, squash
and beans. They often lived in pueblos or
terraced stone and adobe brick homes built
around a square. They were good farmers
who could grow enough crops in a dry place
to support entire villages. Each clan had a
headman. Most Apache lived in a wickiup, a
hut shaped like a dome or a cone of grass and
reed mats over a frame. Each wickiup had a
fire pit and a smoke hole. Navajo lived in
cone or dome-shaped hogans which had six or
eight sides. The doors of hogans always faced
east. A hogan was almost a sacred place
since the Navajo believed the roof
symbolized Father Sky and the
floor was Mother Earth.
Q Why did the Navajo
2. Why did their
population fall?
paint sand?
Europeans carried
diseases which the
native Americans had
not known. They were
unable to fight
smallpox, measles,
bubonic plague,
cholera, typhoid fever,
scarlet fever, pleurisy,
mumps, diphtheria,
pneumonia, whooping
cough, malaria and
yellow fever. Some
groups were wiped out.
The Navajo made
beautiful sand paintings
depicting their gods
as part of a healing
ceremony. The paintings
were done with coloured
powder made from
grinding stones and other
objects they found around
them. They used five shades:
white, black, red, yellow and
blue. The colours were dribbled
on to sand. The sand painters
were guided by the Navajo
priests, called shamans. The
paintings were done at dawn
and wiped out at the end
of the day.
3. Were they prepared
for Europeans?
Battles with the betterarmed Europeans killed
many Native Americans.
As the Europeans
wanted more land, the
tribes were pushed
back. Many could not
adjust to their new
homes and died.
134
A
The shaman
Native American priests, called shamans,
were often the local doctors as well.
Cave dwellings
The cave dwellings of Mesa Verde (Colorado) in which
the Pueblo lived in the twelfth and thirteenth centuries.
Q Were the Native Americans religious?
A Religion was an important part of daily
life for Native Americans. Priests called
shamans practised medicine and
performed rituals. There were rituals
for planting and harvesting. The
Green Corn Ceremony was a
Cherokee thanksgiving festival.
Nothing was taken for granted.
Most Native Americans were
forgiving people and
pardoned all crime except
murder. The Navajo
believed in ghosts, who
they thought were the
spirits of their ancestors.
Q Who are the Inuit?
A Inuit means ‘the
people’. The Inuit people
settled in the Arctic zone in
the extreme north of America.
These people, who probably
migrated to America from
central Asia, adjusted well to
the extreme cold conditions.
Since they could grow little
food, they became expert
hunters. They also became
experts at building igloos,
houses made with blocks of ice.
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Native Americans
Q How did the Inuit hunt?
A For fishing, the Inuit learnt how
to use a harpoon, or a spear with a
strong line attached to it, that could be
hauled back from the water. They also fished
with hooks, lines, or spears with three prongs.
In summer, they dug out roots and berries,
the only plant food in their diet. For meat,
they ate whales, walruses, polar bears and
musk oxen. They often ate meat raw, since
there was little fuel to cook with. The Inuit
trained packs of dogs to work for them,
pulling their sledges and helping them to
hunt. They used the skins of the animals they
hunted to make kayak boats, sleds, tools,
clothes and even homes. The Central Inuit
group or the Caribou Inuit, only hunted land
animals and caught freshwater fish.
Q Who is the Kennewick man?
A In 1996, the skeleton of a man was
found on the shores of the Columbia River
near Kennewick, in the state of Washington,
USA. Radiocarbon dating showed that the
Kennewick man was at least 8,500 years old.
His is one of the earliest human skeletons to
have been found in North America. Five
Native American tribes, led by the Umatilla
of the Columbia River Basin, have argued
that scientists have no right to disturb the
dead. They want the Kennewick man to be
buried once again.
A new monument
The Crazy Horse
Memorial, a mountain
monument being built in
South Dakota to honour
Native Americans.
An Inuksuk
An Inuksuk is a direction
marker used by the Inuit.
Newspaper Rock
On Newspaper Rock in Utah (USA), people have been
recording their activities on stone for 2,000 years.
Frozen home
For centuries, the Central Inuit people
have lived in a igloos or snow homes.
The igloo was made of blocks of ice
laid in a circle like a dome. The ice
bricks were covered with soft snow to
keep out the freezing wind. Stale air
went out through a hole at the top. The
people inside could look out through
a window made of clear ice. The bed
was a platform of ice on which the
residents piled fur sheets. People could
enter and leave through a covered
passage. Most igloos had a smaller
room for storage. What most of us do
not know is that the igloo was just the
winter home of the Inuit. In summer,
they lived in tents made of caribou hide
and in huts made of earth and grass.
Dreamcatcher
The dreamcatcher is a
cultural object among
many Native Americans.
It has a willow hoop and
a net, decorated in
different ways. There
was a belief that it
would protect children
from nightmares.
Try these too…
North America
(110–111), Incas and
Aztecs (141), Discovery
of New Lands (144–145),
The American
Revolution and Civil War
(152–153)
135
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World History
Medieval Europe
Europe in the
Middle Ages.
Western Empire
Brandenburg
House of Luxemberg
House of Austria
Swiss Confederation
England
House of Savoy
France
The Middle Ages fell between the time of the ancient Romans
and the Renaissance, lasting from about AD 500 to 1450.
By AD 500, the western parts of the Roman Empire had begun
to break away. It was a time of endless battles, bloodshed and
struggles for power. During this period, Christianity began
spreading throughout Europe.
Q How did the spread of Christianity affect
medieval Europe?
A Although other religions existed in
Joust
Duels between armed
knights, known as jousts,
were common during the
Middle Ages.
Quick Q’s:
1. What was a castle?
A castle was the home
and fortress of a lord
or king. They had
ramparts from which
soldiers could attack
the enemy if the castle
was besieged. Many
people besides the lord
lived in it, including
servants, soldiers,
cooks, blacksmiths
and falconers. Cows,
horses, pigs and
chickens were also
kept there for food.
2. What did people
wear?
Knights wore sleeveless
coats decorated with
their coat of arms. Rich
men wore cloaks. Rich
women wore tunics
that reached to their
ankles. Married women
tied their hair in a bun
and wore tight caps
and nets over it.
Unmarried women
could leave their hair
loose or braided.
136
Europe, the Catholic Church ruled the lives
of most people. It laid down its own laws,
owned land and levied taxes. The Church
was based in Rome and headed by the Pope,
but it also ruled from monasteries located in
different parts of Europe. The Church was
all-powerful, and people who openly spoke
out against it risked being branded heretics
and burned alive at the stake.
The power of religion
The Catholic Church ruled every aspect of life in
medieval Europe. It decided who lived where and how.
It also controlled marriages and burials.
The keep
Most forts had a high
and strong keep to
which defenders
could retreat if
necessary. Many of
the keeps had secret
tunnels for
escape.
Keep
Q
How were the various
kingdoms governed?
A Much of western Europe was ruled by
the feudal system. The king distributed land
among noblemen in return for services and
loyalty. Poor peasants rented this land from
the nobles, and often paid them with
livestock, eggs, firewood or wine. The nobles
lived in a castle or a manor house.
Q How did the Crusades begin?
A The Crusades were a series of battles
fought between Christians and Muslims. In
AD 1095 Pope Urban encouraged Christians
to free Jerusalem from Muslim rule. Several
unorganized groups set off before they could
be formed in to an army. Most of them died
along the way. The main Crusaders left for
Jerusalem in late 1096. They captured
Jerusalem and other cities. This started a
series of wars that went on for over 300 years,
known as the Crusades.
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Medieval Europe
Heroic thief
Robin Hood is a legendary hero whose
story began in medieval England. He and
his band of 140 men lived in Sherwood
Forest in Nottinghamshire. They fought
against the poverty and injustice of the
feudal system by robbing the rich and
giving what they stole to the poor.
Q Did King Arthur exist?
A Historians are not sure whether King
Arthur was a legend or based on a real king.
Some think he may have been a Celtic warrior
who fought the invading Anglo-Saxons in the
late fifth century. Stories about him have
been popular since the twelfth century.
Try these too…
Europe (116–117),
Ancient Greece
(128–129), Ancient
Rome (130–131), The
Renaissance (142–143),
Architecture (164–165)
Q Who were the Vikings of Scandinavia?
A The Viking Age occurred between the
eighth and eleventh centuries. The Vikings
came from Denmark, Norway and Sweden.
Most Vikings were farmers who were also
great travellers and explorers. They travelled
in winter when they could not farm. They
were fierce warriors who attacked the coasts
of Europe in their longboats, capturing new
lands to farm. Many of these attacks were very
violent and earned the Vikings a reputation
for being barbaric. The Vikings settled in
colonies in Scotland, Iceland, Greenland,
Newfoundland in Canada, and many other
places along the shores of the Atlantic Ocean.
Couple from the
Middle Ages
Rich people wore long
and heavy cloaks.
Garbage disposal
The habit of throwing
garbage on to the street
led to many diseases.
Q What was the Black Death?
A In the mid-fourteenth century, the
bubonic plague broke out in Europe. It
began as a disease of flea-infested rats, but
quickly moved to people and spread like
wildfire. It is likely that it was carried from
the East along trade routes and by Crusaders
returning to western Europe. It killed
around 25 million people within five years.
It was called the Black Death because of the
black-coloured boils that appeared on the
victims’ skin.
137
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World History
Medieval China and Japan
By about AD 500, the world was becoming more connected.
Technology had improved, allowing people to travel more and
learn from each other. With more trade and travel, religions
started to spread. This was the period during which Buddhism
spread in China and Japan.
Quick Q’s:
Q Which was the first major dynasty to
1. What was the Silk
Route?
rule China during this era?
The Silk Route was an
important trade route
that began in China
and ran across Central
Asia, all the way to
Europe. Silk was the
cloth worn by royalty in
China. This land route
was important until the
early sixteenth century.
2. What is origami?
The Japanese
perfected the art of
folding paper into
three-dimensional
figures and shapes.
Origami may have
come to Japan with
Buddhist monks from
China. Others believe
Origami is an art form
that was developed in
Japan. Only a few folds
are used in Origami,
but the folds can be
combined in a variety
of ways to make
complicated designs.
Most Origami designs
begin with a square
sheet. The two sides
may be in two different
colours. Usually, the
paper is not cut.
A The Han dynasty had a long rule from
Q What were the major developments
206 BC to AD 220. This was enough time for
a strong dynasty to bring most of modern
China together. Under a long line of strong
rulers, stability and peace spread. The Han
dynasty saw the development of Chinese
philosophy. This was also the time when a
new religion came to China. Missionaries
from India brought Buddhism, a religion
that preached peace. Many Chinese people
converted to Buddhism.
of this period?
Q Why is the Tang dynasty famous?
A During the Sui dynasty ( 589–618),
AD
cultural changes began in China. Then
came the Tang period, between AD 618
and 907. This is known as the Golden Age
of China. Learning and the fine arts
developed like never before. When the
young king Tang T’ai-tsung took over in
618, he made the government stable and
strong. This encouraged agriculture and
trade, and China grew prosperous. The arts
flourished. Talented people did a lot to
improve landscape painting, music, poetry,
ceramics and metalwork. Sculpture became
popular. Buddhist art was developed.
Tang stone pagodas and paintings from
the Dunhuang caves are fine
examples of art from this age.
Folded paper
Origami, the Japanese art of folding paper, uses
a small number of different folds. They can be
combined in a variety of intricate designs.
138
Medieval
China and
Japan
A As early as
AD 105, the Chinese knew
how to make paper and how to print. They
perfected printing and used wooden blocks
to print books. Science was also prospering.
China gave the world the compass. While
Europe struggled to fight the plague, China,
Korea and Japan were developing rapidly.
However, some strange ideas also crept in.
Mongol emperor
Genghis Khan (1162–1227)
was the first of the great
Mongols. He brought
China, Tibet, Burma, Iran,
Eastern Europe, and parts
of Russia under Mongol
control. In 1234, the
Mongols had northern
China in their grip. It took
them some time to bring
the rest of this vast
country into their fold.
During the Sui dynasty, around AD 500,
the emperor ordered that only the rich would
wear colours and the common people would
wear blue or black. During the Sung dynasty,
around AD 1100, a painful sign of nobility
was used. The feet of little girls were bound
so tight that they never grew more than 7.6
centimetres (3 inches) long. The bandages
broke the toes of girls as young as five years
old. The toes bent under the feet. As women,
they could barely walk. These lily feet were
in fashion for over 1,000 years until they
were banned in 1912.
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Medieval China and Japan
Delicate work
The artefacts made in medieval China were of porcelain
stone. China clay was added in the eighteenth century.
It increased the strength of the artefacts.
Q What did the Chinese take to Japan?
A Around the fourth century, Chinese
Q Why is the Ming dynasty so famous?
A The Mongols, who ruled China for 89
years, were overthrown by Hung-Wu in AD
1368. That marked the start of the Ming
dynasty, which lasted until 1644. The Ming
dynasty is remembered for making the
administration strong, widespread and fair.
Judges had to take a test to get a job.
Chinese literature, art and philosophy
reached new heights during Ming rule.
Some of the best Chinese porcelain was
manufactured at Jingdezhen. The yellow
imperial bowls, red vases and highly
decorated painted ceramics became popular.
For the first time, both cotton and silk
production did very well.
Q Who were the shoguns?
A Across the sea, Japan saw a long period
of peace under the Seii Tai shogun or
shoguns, military dictators who ruled from
1192 to 1867. The term means ‘barbariansubduing generals’. Minamoto Yoshinaka
was the first modern shogun, who came to
power after defeating the Taira dynasty.
The shogun rulers had loyal warrior servants
known as samurai. Samurai is from the
Japanese word saburau, which means ‘to
serve’. Japan developed far slower than China
because it was a group of islands, cut off
from the mainland of Asia. It was only in
AD 405 that the Japanese adopted a written
language and even then they developed a
writing system based on the pictorial alphabet
of the Chinese.
settlers taught the Japanese how to grow and
weave silk. The Japanese wore hemp clothes
before that. In the sixth century, Buddhism
spread among the Japanese from China.
Japanese art of this period includes wooden
and bronze statues of Buddhist figures,
landscape paintings and scroll paintings. The
Japanese built magnificent pagodas. Literature
developed. The Chinese also taught them a
form of theatre. The Japanese combined it
with their own comic plays and created a new
form, the noh. The Japanese learnt about tea
from the Chinese in the ninth century. They
later developed a ceremony around it. The
Tale of Genji, one of the earliest Japanese
classics, dates to the eleventh century.
Try these too…
Asia (120-121), Ancient
India and China
(126–127), Discovery of
New Lands (144–145),
Architecture (164–165),
Theatre (170–171)
World heritage
Built in stages between
1346 and 1601, Himeji
Castle is one of the best
examples of medieval
Japanese architecture.
National dress
Kimono, in Japanese, means
clothing. In recent years, it has
come to mean a traditional
Japanese robe. Kimonos came
into fashion during the Heian
period (794–1192). Before that,
the Japanese wore separate
upper and lower garments, or
one-piece robes. In the Heian
period, a new stitching technique
led to the kimono. Cut in
straight lines, these kimonos
were suitable for all weather.
As techniques improved, so did
the kimono. They even became
family heirlooms. The kimono
was the most popular garment
in Japan until about 50 years
ago. Today, the kimono is only
worn on special occasions like
the tea ceremony.
139
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World History
Mughal India
In 1526, Babur, a Turk from central Asia, occupied Agra in
northern India. He expanded his influence throughout the
region and founded the Mughal Empire. The Mughal Empire
continued until 1857.
Inlay work
Inlay work on stone
reached its height in
Mughal India. It was used
to decorate mosques,
mausoleums and palaces.
Q
How did the Mughals keep the
Empire together?
A The Mughals had a central government.
Quick Q’s:
1. What does
Mughal mean?
Mughal comes from
the Persian word for
Mongol. The first
Mughal Emperor
Babur was from a
Mongol family.
2. What is the
Taj Mahal?
The Mughals loved
architecture. They built
complicated and
intricately decorated
mosques, tombs and
strong forts at Agra
and Delhi. They also
studied the science of
landscaping and
created beautiful
gardens. Shah Jehan
built the Taj Mahal as a
tomb for his beloved
wife, Mumtaz Mahal.
3. Who were
the navratna?
Navratna means nine
jewels in the Hindi
language. These were
nine talented men in
the court of Akbar.
They were given special
powers. They included
Tansen the singer,
Todar Mal the
administrator, Abul
Fazl, the emperor’s
chief advisor, and
Maharaja Man Singh,
Akbar’s trusted general.
140
Mughal India
Q Who was Akbar?
A Babur’s grandson Akbar was the greatest
of the Mughal emperors. He expanded the
empire to cover most of northern India. His
reign brought peace and prosperity. Although
Akbar could not read or write, he encouraged
philosophers, poets, artists, architects and
musicians. He died in 1605. His son Jehangir
and Jehangir’s son Shah Jehan enjoyed long
and prosperous reigns. For the first time, the
Mughals gained control of western India.
Under Shah Jehan’s son Aurangzeb the
Empire covered almost all of south Asia.
The Emperor was supreme. The highest
nobles were mostly central Asians, Persians,
Afghans, Indian Muslims and Rajputs. The
Mughals won over the powerful Hindu
Rajputs partly through conquest, and partly
by respecting their customs. Akbar married
Joda Bai, a Rajput woman. He even tried to
start a new religion that included elements
of all existing faiths in India. No single group
was allowed to become powerful enough to
threaten the Emperor. Tax was paid in cash,
which was spent on creating new towns and
markets. European traders visited Mughal
India frequently and trade prospered.
Poetry in stone
The Taj Mahal in Agra, India.
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Incas and Aztecs
Incas and Aztecs
The Incas and the Aztecs ruled the last ancient empires of Latin
America. The Incas expanded their kingdom in the twelfth
century, and by the early sixteenth century, they had more land
than any other people in South America. The Aztecs had their
empire in Central America, in today’s Mexico.
The Inca empire
Q What did the Incas do for a living?
A The Incas were good farmers, even
Q Who were the Aztecs?
A The Aztec were the last tribe to arrive in
though farming was difficult in the Andes
mountains, where they lived. They carved
terraced fields, where they grew corn, chilli
peppers, beans, squash, peanuts, cassava,
quinoa and potatoes. They knew how to
irrigate their fields. They used tools like
spades, clubs, hoes, sticks and foot ploughs.
The Incas domesticated animals like the
llama and alpaca for wool and to use as
transport. They were good at construction
and fitted gigantic stone pieces together
without using mortar. They built bridges
and tunnels through the mountains. They
studied medicine and performed operations.
They worshiped many gods and believed in
heaven and hell. Of all the gods, the Sun
God was the most important, and they built
many temples in his honour. When an Inca
king died, his body was mummified. People
would offer the mummy food and consult
it to solve problems. Ordinary people were
also mummified, but they were buried.
Central America. In 1325, they founded the
city of Mexico-Tenochtitlan. They built one of
the strongest armies in the region. Between
1428 and 1521, they had the largest empire in
Central America. The Aztec Empire fell in
1521, when they were defeated by the Spanish
General Hernan Cortes.
Spanish invader
Spanish General Francisco
Pizzaro defeats the Incas
in battle. The Incas had
a large and disciplined
army, but they could
not hold out against
the Spaniards.
Try these too…
North America
(110–111), South
America (112–113),
Ancient Americas (132)
Terraced farming
Terraces on mountain
slopes held soil and
water and allowed the
Incas to farm the slopes.
The Incas developed
new techniques to build
the terraces.
A bridge made of grass
The Incas were good with their hands. They knew how to plait
grass into strong rope. They built suspension bridges with this
rope which they wove together (as shown here). Some bridges
were 61 to 91 metres (200 to 300 feet) long. Although made of
grass, they lasted several hundred years.
Q What happened to the Incas?
A In 1531, a Spanish General named
Francisco Pizarro invaded the Inca with only
two hundred soldiers. He tricked the Inca
ruler, Atahualpa, into meeting him in
Cajamarca. Pizarro then kidnapped him and
killed hundreds of his family and followers.
Atahualpa was killed in 1533. Different Inca
tribes did put up resistance for 30 years, but
the Spanish defeated them. This ended the
largest and richest South American empire.
141
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World History
The Renaissance
The European Renaissance lasted from about 1450 to 1650. The
French word Renaissance means rebirth. This period brought an
end to the Middle Ages and marked the start of the modern
world. Every part of life, including art, politics, trade and
learning took a new turn. The Renaissance began in Italy, and
spread throughout western Europe.
Quick Q’s:
1. Did the Renaissance
change music?
During the Renaissance,
musicians learnt many
things about the science
of sound waves, which
helped them to create
the kind of music they
wanted. Composers
studied Greek drama
and were inspired to
create the opera.
Q What led to the Renaissance?
A Italy, surrounded by sea on three
sides, was a centre of trade. More money
and exposure to other cultures led people to
expand their ideas. They were also inspired
by the ancient cultures of Greece and Rome.
People were eager to learn, and they studied
literature, art, history and science. For the
first time, art and literature were not
restricted to religious subjects.
2. Who was Mona Lisa?
The Mona Lisa is
probably the most
famous painting ever
created. It was painted
by Leonardo da Vinci.
The model is said to
be Lisa Gherardini,
who was the wife of
a nobleman. The
painting is in the
Louvre, Paris.
3. What was in fashion
in Renaissance
Florence?
Women shaved or
plucked off their
eyebrows. Even the
Mona Lisa has none.
Q What was Renaissance literature about?
A Renaissance literature was based on
Greek and Roman classics. The poetry
of Francesco Petrarch and the stories of
Giovanni Boccaccio in Italy, as well as the
witty writing of Desiderius Erasmus in
Holland and François Rabelais in France
were among the new forms of literature
that recalled the Greek and Roman classics.
People realized that there were many forms
of literature apart from religious books.
Major authors like Shakespeare changed
the way people looked at themselves and
at the world around them. Many forms of
literature today, like the novel, owe their
birth to Renaissance ideas.
Hans Holbein the Younger (1497–1543)
A German painter famous for his portraits, Hans Holbein
the Younger painted the king and many of the nobles in
the court of England.
The Last Judgment
This is a detail from the famous fresco painted by
Michelangelo on the ceiling of the Sistine Chapel
in the Vatican.
142
Statue of Dante in Verona, Italy
Dante (1265–1321) was an Italian poet, famous for his
work The Divine Comedy. He had a major influence on
later Renaissance poets and writers.
Q What was special about Renaissance art?
A Artists became interested in drawing the
human figure as it really is. They learned to
use light and shadow. Wall paintings on wet
plaster (called fresco paintings) became
common, as did tempera paints that were
mixed with egg yolk. Oil painting became
popular towards the end of the Renaissance.
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The Renaissance
Master painter
Q Who were the most famous artists?
A Leonardo da Vinci, Michelangelo and
The Marriage of the
Virgin – a painting by
Raphael (1483–1520),
one of the best artists
in Italy during the
Renaissance. This famous
painting is now in Milan.
Raphael in Italy, and Durer in Germany,
were the most famous artists of the
Renaissance. Leonardo da Vinci created
paintings like the Last Supper and the Mona
Lisa. Michelangelo created sculptures such
as the Pieta and painted the roof of the
Sistine Chapel in the Vatican. Raphael
painted the Pope’s apartments, also in the
Vatican. Durer created engravings like Knight,
Death and the Devil. All these are still admired
by millions of people today.
Martin Luther
Martin Luther (1483–1546)
reformed the Church,
founding what became
known as the Protestant
Church.
Q Who was Gutenberg?
A Gutenberg invented Europe’s first
printing press with moveable type in 1445.
The first book he printed was the Bible.
The printing press meant books were much
cheaper and easier to produce than before.
It allowed people to read the work of ancient
scholars, whose work had been forgotten
during the Middle Ages. It also meant that
books were available to many more people.
People who had never seen books before
could now learn to read and expand their
horizons and their ambitions.
Q Did science play a part in
the Renaissance?
A During the Renaissance, Italians were
able to travel further because of tools they
had invented, like the astrolabe and the
magnetic compass that helped sailors figure
out where they were going. More travel
meant more trade, which made the Italians
richer. These rich Italians commissioned
artists to paint their portraits. During the
Renaissance, science played a part in other
ways too. The famous painter Leonardo da
Vinci started dissection of dead bodies, and
that increased the knowledge of the human
anatomy many times over.
Try these too…
Europe (116–117),
Ancient Greece
(128–129), Ancient
Rome (130–131)
Shakespeare was a Renaissance man
The Renaissance in
England is also known as
the Shakespearean age.
It was England’s golden
age of literature,
architecture, science
and exploration.
Literature prospered
more than any other
form of art. William
Shakespeare was one
of the most important
English playwrights
during this period. He
wrote about 38 plays
and hundreds of poems.
His plays are still loved
and performed today,
almost four hundred
years after his death.
143
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World History
Discovery of New Lands
Between the fifteenth and the seventeenth centuries, Portugal
and Spain stepped up their exploration of sea routes. France,
Germany, England and the Netherlands also sent out explorers
to find new lands. This period became known as the Age
of Exploration. Apart from the spirit of adventure, the
explorers were driven by the desire to spread Christianity
and the hope of getting rich.
Quick Q’s:
1. How did technology
help improve sailing?
New gadgets made
sailing more accurate
and safe. The
chronometer was a
special clock that kept
time even on rough
seas. The compass
helped the sailor find
his way. The astrolabe
helped predict the
position of the Sun,
Moon and stars as well
as tell time.
2. How did the Pacific
Ocean get its name?
Ferdinand Magellan
gave the Pacific Ocean
its name, which means
peaceful or calm. After
battling past the
fierce Cape Horn
at the tip of South
America, he found
the Pacific Ocean
unusually still.
3. What did the sailors
bring home with them?
The sailors brought
riches and spices from
the new lands. Foods
like potato, tomato and
chilli were introduced.
Animals like jaguar
and tapir, and birds
like macaw and toucan
were brought for the
zoos of Europe. Many
shipowners became
very rich carrying gold
and other treasures for
the government.
144
Q How did these navigations begin?
A The Vikings of Scandinavia were the
earliest seafaring people to cross the Atlantic
Ocean. They discovered Iceland, Greenland
and Newfoundland, and sailed along the coast
of Canada long before other European
countries set out in search of new lands.
During the period from 870–930 AD, the
Vikings began to settle in Iceland. In 930 the
ruling chiefs established a parliament there.
In 982, a Viking called Eric the Red sailed
from Iceland and discovered Greenland.
Nearly 20 years later, his son Leif Eriksson
discovered Newfoundland.
Essential device
The invention of
the astrolabe
allowed European
sailors to travel
around the world.
This model has
been kept in a
park as an exhibit.
Sea routes taken by great explorers.
Magellan
Vasco da Gama
Columbus
Q Who were the most adventurous sailors
from western Europe?
A The Portuguese were the first to begin
exploring sea routes in the fifteeenth century.
Portugal’s Prince Henry the Navigator was a
great patron of seamen. He was a devout
Christian and dreamt of spreading the
religion to new lands. In 1434, his ships
landed on the west coast of Africa. Various
Portuguese ship captains kept going further
and further south along that coast. About
fifty years after the first landfall in western
Africa, another Portuguese explorer,
Bartholomew Diaz, was the first to go around
the southern tip of Africa – the Cape of Good
Hope. In 1497, Vasco da Gama followed this
route to reach India. He first went around
the Cape of Good Hope and then reached
the island of Madagascar off the eastern coast
of Africa. Then, with the help of an Arab
pilot, he followed the trade winds and
crossed the Indian Ocean. Vasco da Gama
became the first European of his age to reach
southern India. Ferdinand Magellan set out
in 1519 to find a western route to the Spice
Islands. He reached the Philippines in 1521
where he was killed in a battle. However,
three of the ships he led returned to Europe.
This was the first expedition to sail around
the world and return home in triumph.
Vasco da Gama reaches India
A contemporary sketch showing the meeting between
the Portuguese explorer Vasco da Gama and the ruler of
Calicut in southern India.
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Discovery of New Lands
Q Who was Christopher Columbus?
A Born in Genoa, Italy, in 1451,
Q Where did the British expeditions go?
A John Cabot led the first British
Christopher Columbus began sailing when
he was just 14 years old. He had read that the
world was round. While most explorers were
going east on the longer and more dangerous
route discovered by Diaz, he decided to go
west and come all the way round to the Far
East so that he could find new trade routes
to Asia. After petitioning for funds for ten
years, Columbus was given a grant by King
Ferdinand and Queen Isabella of Spain. The
grateful Columbus promised to bring back
gold, spices and silk from the Far East and
to spread Christianity. In return, he asked to
be made a governor of all the lands that he
discovered. On his first voyage he discovered
an island in the Bahamas and Cuba. Between
1493 and 1502, Columbus made three more
voyages, hoping to see more of what he
thought was Asia. During these trips he came
upon more Caribbean islands including
Jamaica, Trinidad and Tobago and Grenada.
He also discovered Honduras, Nicaragua and
Costa Rica in Central America and Venezuela
in South America. Until he died, Columbus
thought he had reached India, when in fact
he had discovered America!
expedition to the West. Like Columbus, he
wanted to find a shorter and safer route to
the spice-producing countries of the East.
In 1497 Cabot landed in Newfoundland,
Canada. Between 1576 and 1578, Martin
Frobisher made three voyages to Canada
and claimed a large part for England. In 1580,
Sir Francis Drake was the first Englishman
to sail around the world. His fleet of five ships
sailed nearly 57,936 kilometres (36,000 miles)
in 34 months. James Cook made three
voyages between 1768 and 1779. On the first
he charted New Zealand and the east coast
of Australia. On the second he found several
South Pacific islands and crossed the Antarctic
Circle. On his last voyage he discovered
Hawaii and then sailed up north to Alaska.
Try these too…
Oceans (34–35), North
America (110–111),
Mughal India (140), The
Renaissance (142–143),
The British Empire
(146–147), The
Industrial Revolution
(148–149), Scientific
Revolution (150–151)
Spicy trail
Europeans sailed all over
the world in search of the
spices of the East.
All for a name
The German cartographer Martin Waldseemüller liked to make
up names. He even created his own surname. In honour of
Amerigo Vespucci’s discovery, Waldseemüller printed a map
called Carta Mariana. He named the southern part of the New
World America. The northern part was called Indies at this time.
A thousand copies of this map sold out. Waldseemüller changed
his mind about the name America a few years later, but by then,
it had already become popular.
Q How was America named?
A America was named after the Italian
traveller Amerigo Vespucci. Vespucci had
studied books and maps under Michelangelo.
Vespucci was a banker. He went to Spain in
1492 where he became interested in sailing.
His first expedition was in 1499 as a navigator.
He and his crew reached the mouth of the
Amazon River and explored the coast of
South America. He calculated how far west he
had travelled. In 1501, he sailed around most
of South America. He was the first to realize
that the ‘New World’ of North and South
America was not in Asia. He made three trips
to the New World and made a number of
calculations before he died of malaria.
145
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World History
The British Empire
In the fifteenth century AD, the Age of Exploration led to the
Age of Imperialism. Europe became rich and powerful because
of its conquests of various countries in other continents. Spain
and Britain were great rivals for overseas territories. In 1588, the
British defeated the Spanish Armada and became a major world
power due to the strength of its navy. English merchants were
also tempted by the spices, silk and gold of the Far East.
Quick Q’s:
Q Did the English monarchy encourage
1. Which was the first
British colony to gain
independence?
sailors to find new territories?
In 1776, thirteen
British colonies in
North America signed
the Declaration of
Independence. They
formed the United
States of America.
2. What was special
about the colony
in Australia?
Between 1788 and
1853, thousands of
English criminals were
shipped off to Australia
because the English
jails were too full to
house them. These
were the first British
settlers in Australia.
A In the 1490s, when Spain and Portugal
were charting new sea routes, British sailors
were also busy. Encouraged by Henry VII,
John Cabot was looking for a trade route to
China across the Atlantic. He reached North
America in 1498, while searching for an
alternative route to India. In the sixteenth
century, Sir Francis Drake set out to look for
the East Indies. He was a favourite of Queen
Elizabeth I, who not only encouraged
explorers to find new lands, but also to
establish British settlements in these regions.
Q Who were the first people to settle in
the United States?
A The colonization of North America
Company flag
The British East India
Company was given the
Royal Charter by Queen
Elizabeth I in 1601 to
trade in India. In 1617, the
company was given trade
rights by the Mughal
Emperor who then ruled
much of India. It
established its military
power in parts of India
after winning the Battle
of Plassey in 1757.
146
really started with the Plymouth
Company of religious pilgrims. It was
the first permanent English settlement
overseas. The pilgrims left England in
their ship, the Mayflower, in September
1620 and headed for New England in the
United States. They set up their first village
and named it Plymouth.
Defeating the Armada
The defeat of the Spanish
Armada at the hands of the
British paved the way
for the British Empire.
British colonies
Spanish colonies
French colonies
Portuguese colonies
Q When did the British go to India?
A At the end of the sixteenth century,
the East India Company was formed. The first
Indian warehouse to store spices, textiles and
a textile dye called indigo was built and the
first ship left with this cargo for England
in 1615. During this period, the British
fought the Dutch and the Portuguese
repeatedly in the
Indian Ocean.
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The British Empire
Q How far did the British Empire reach?
A By 1687, the British in India moved on
Q How did the Empire collapse?
A The British needed educated people
to Bombay, which Charles II was given as
a wedding gift by his Portuguese bride,
Catherine of Braganza. With colonies from
North America to Africa, India, Sri Lanka,
some Southeast Asian countries, several
South Pacific Islands, and all of Australia
and New Zealand, Britain became the largest
imperial power between the sixteenth and
the nineteenth centuries. It held nearly
one-third of all the land in the world.
to work for their trading companies in
the colonies. So, they taught the native
people English and provided all branches of
western education in the colonies. This
education, especially in the social sciences,
exposed the residents of these countries to
ideas of democracy and self-rule. As a result,
political parties were formed in the colonies,
and these parties began to demand
independence from British rule. On top of
this, the two World Wars left Britain
economically weaker than it had been for
centuries, Britain found it difficult to raise
the money required to administer the
colonies. In 1947 India became independent.
Most other Asian and African countries
became independent by the 1960s.
Q Did other countries have colonies?
A The Portuguese had the large colony of
Brazil in South America, as well as Angola
and Madagascar in Africa. They also held
small enclaves in many other parts of the
world. The French colonized much of
northern, western and central Africa;
Lebanon and Syria in the Middle East;
Vietnam, Cambodia and Laos in Southeast
Asia. They also had small colonies in the
Caribbean islands, South America and
some of the islands in the Pacific Ocean.
The Dutch had a large colony in what is
now Indonesia, a group of islands in Asia.
Try these too…
Discovery of New Lands
(144–145), The Industrial
Revolution (148–149)
Sceptical statesman
Benjamin Disraeli was
a nineteenth-century
politician sceptical
about the benefits of
the Empire.
A common history
Fifty-three countries, which have all been colonies of Britain,
form the Commonwealth of Nations. These are independent
states that have their own governments. These countries help
each other in trade and other areas. The Queen of England is
still the queen of 16 former colonies, which are called the
Commonwealth Realms. These countries compete in the
Commonwealth Games every four years – the world’s
second-largest sporting event after the Olympics.
Q How did Britain govern such a large
territory around the world?
A Britain was able to hold on to so much
land so far from home since her officials
dealt with each of the colonies as the
situation demanded. In Asia and Africa,
Britain first set up trading companies, which
started by dealing with local rulers and
setting up trading posts. With time, these
companies grew and supported organized
armies. At that stage, local rulers were won
over or defeated, while the British gained
territory. Britain also sent thousands of its
citizens to colonize North America, Australia
and New Zealand.
147
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World History
The Industrial Revolution
Towards the end of the eighteenth century, western society
experienced major changes because of new and improved
machines that helped make more goods faster. This period of
change lasted for about a century and is known as the Industrial
Revolution. In other parts of the world, replacing manual work
with machines began later. In some places, it is still going on.
Quick Q’s:
1. What were some of
the early machines
like? What did they do?
Machines helped speed
up almost all kinds of
work. In 1563, Rev
William Lee of
England invented the
Stocking Frame to knit
stockings with.
2. What was the Cotton
Gin meant for?
In 1793, Eli Whitney,
an American, invented
the cotton gin to
remove seeds from
cotton. Until then,
African slaves spent
hours removing the
seeds by hand.
3. Did the Industrial
Revolution have any
disadvantages?
The Industrial
Revolution brought
obvious advantages –
health improved and
more people were
educated. However, it
created huge slums
and shanty towns
where people with less
money lived in
unhygienic conditions.
Some turned to crime.
Roads and cities were
built, wiping out forests
and important
environmental sites.
Factories burning fuel
spread pollution, the
effects of which are still
being felt.
148
Q Where did the Industrial Revolution start?
A The home of the Industrial Revolution
was in Britain. By the eighteenth century,
Britain was one of the richest nations in the
world. It had supplies of coal and iron, two of
the most important raw materials of industry.
Inventions like the steam engine had
improved transportation. More roads were
built. Canals were dug for barges and these
were used to move raw materials to factories
and take finished goods to cities and ports.
Q How did manufacturing change?
A Machines took over most types of
manufacturing. Before the Industrial
Revolution, about 70 per cent of the work
was done by muscle power and with simple
tools. During the Industrial Revolution, people
began to burn coal instead of wood. This
provided more energy to produce more goods.
The iron horse
The steam engine was
improved by James
Watt (1736–1819) so
that it could be used
to pull trains and
in factories. Trains
opened up vast new
areas to development.
Iron – the most important metal in
industry – could now be made into different
shapes. Iron was used to make more
machinery and other industrial equipment.
Q How did the Industrial Revolution
change society?
A The effects of machinery were first seen
in agriculture. In 1708 Jethro Tull’s seed
sower helped plant seeds in neat rows very
quickly. The machines did the work faster
and better than people. Many farmers had to
move to cities and work in factories. Things
that used to be made at home or in small
workshops were now mass-produced.
Handicraft that had developed over hundreds
of years died out. Cities grew larger. Soon, the
Industrial Revolution spread to other parts of
Europe and America. Since countries were
rivals for buying and selling goods, they
needed larger armies to help them.
Bicycle factory
One of the early factories
of the Industrial Age,
this bicycle factory
used methods of mass
production originally
developed in the United
States by Henry Ford
for the Model-T Ford car.
Mass production allowed
factories to make many
products exactly like
one another, far more
quickly and cheaply
than before. A greater
range of products was
manufactured, and more
people could afford them.
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The Industrial Revolution
Q What were the major areas of
manufacturing that changed?
A
Once people learnt to use iron in
different shapes and forms, rail tracks and
engines improved. They made transportation
of men, machinery and raw materials easier
and faster. The first steam pump was
developed in 1689. James Watt improved on
it and used it for trains. It was also used for
steamboats. Textile manufacturing really
improved in the early part of the Industrial
Revolution. In 1733, John Kay came up with
the flying shuttle that speeded up weaving.
In 1770, James Hargreaves invented the
Spinning Jenny, which could spin a number
of threads at once. By 1779 Samuel
Crompton had made The Mule to spin finer
thread. With so many improvements, Britain
could supply cloth throughout the world.
Q Did other countries benefit from the
Industrial Revolution?
So iron and steel and other heavy
industries grew quickly there. The Industrial
Revolution spread across Europe, often
helped by inventors in other European
countries and in the United States.
Flying shuttle
The shift from handloom
to power loom for
weaving made the
manufacture of cloth
much faster.
A Britain’s financial success encouraged
other countries to turn to
industry. France, Germany,
Holland, Belgium and the
United States joined the
Industrial Revolution.
The United States soon
overtook Britain as a
global industrial
power, to become
the world
leader. This
period of
growth is
called the
Second
Industrial Revolution. In the United States,
land and other natural resources were
available in plenty. By 1851, the United States
had the most advanced mechanical
inventions to show at the industrial fair at
Crystal Palace in London. Germany had huge
deposits of iron and coal needed by industry.
Try these too…
Discovery of New Lands
(144–145), Scientific
Revolution (150–151)
In good company
Technical companies started springing
up in the eighteenth century. In 1775,
James Watt joined Matthew Boulton
to start an engine-building and
engineering company that would solve
technical problems in factories. There
were many such companies that helped
to improve industry. Businesses had
to develop new ways of working and
become organized into corporations.
People were employed to manage these
businesses. Management became a
profession and a course of study at many
universities, especially in the USA.
Communication
revolution
The first telegraph
machine developed
by Samuel Morse. This
made it possible to send
messages over long
distances almost instantly.
149
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World History
Scientific Revolution
The Scientific Revolution between 1550 and 1727 marked a change
in the way that people thought about science. It was sparked by
Copernicus and then spread across western Europe. Sir Francis
Bacon spurred on this change when he said that science should
be based on observation and experiments. To this day, these are
the foundations of science and a scientific temperament.
Q Who was Copernicus?
A Nicholas Copernicus (1473–1543) is
Bloodletting
During the Middle Ages,
it was believed that
removing blood would
cure diseases.
regarded as the father of the Scientific
Revolution. He claimed that the Sun is at the
centre of the universe and that the Earth
rotates on its axis once a day and revolves
around the Sun each year. At the time, this
claim shocked and upset people because they
had always believed that the Earth was at the
centre of the universe and that the Sun went
around the Earth.
Q Who coined the term Scientific
Revolution?
Quick Q’s:
1. How important was
the Scientific
Revolution?
Before the Scientific
Revolution, people did
not question the way
things worked and
many people were
superstitious. The
Scientific Revolution
challenged such ideas.
2. What was the most
important scientific
study of the time?
In 1687, in his
Mathematical Principles of
Natural Philosophy, Isaac
Newton explained ideas
such as gravity, force,
mass and acceleration.
People now understood
how substances attract
each other and how the
Earth exerts gravity.
150
A The term Scientific Revolution was given
to this period of change in 1939 by Alexandre
Koyre. The Scientific Revolution began with
astronomy and then shifted to physics and
anatomy. The most astounding progress in
chemistry and biology only came in the early
eighteenth century. Changes happened in
theory and experiments as well as in the way
scientists worked and thought.
Q Were there any new discoveries in the
Revolutionary man
Nicholas Copernicus, seen here with his model of the
solar system, changed the way we see the world.
Antony van Leeuwenhoek made a single
lens microscope which made studying the
tiniest details of the world around us possible.
Q Who were the first scientists to study
electricity?
A William Gilbert studied magnetism and
its relationship to electricity in 1600. He
discovered the Earth’s magnetic field, which
makes the Earth act like a huge magnet.
The needle of a compass always points north
because of this magnetic field. Gilbert was
the first person to use the term electricity.
life sciences at this time?
A In 1543, Andreas Vesalius found that
blood circulated in the body because the
heart acted like a pump to push it around.
He worked with dead bodies and put together
the first complete human skeleton. William
Harvey also dissected human bodies to show
how blood circulates through the body.
Knowing the
direction
Once it was
discovered that
the compass
points to the
magnetic north,
navigation
improved.
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Scientific Revolution
Q When did the Scientific Revolution end?
A The Scientific Revolution is said to
have come to an end with the death of
Isaac Newton in 1727. He took the work
of Johannes Kepler and Galileo further.
He developed calculus and showed how
mathematics could be used in science.
He also established the laws of gravity.
Medical textbook
An early drawing of human anatomy by Andreas
Vesalius (1514–1564) in his book De Corporis Fabrica
(What The Body Is Made Of). The book changed the way
medicine was studied.
Q Who was Galileo?
A Galileo Galilei was an Italian astronomer
and physicist who supported the theories of
Copernicus. He improved the telescope and
made so many new observations about the
planets that he has been declared the father
of science. He discovered the four biggest
moons of Jupiter. However, during his
lifetime, Galileo struggled against the Roman
Catholic Church. The Church banned his
work on the planets because it was so
different from what the scriptures said. He
was put under house arrest for insisting that
the Sun is at the centre of the solar system
and remains in one place. The Church
forced him to change his views in public,
but he held on to them in private.
Try these too…
Discovery of New Lands
(144–145), The
Industrial Revolution
(148–149), The World
after World War II
(160–161), Computer
Revolution (162), The
New Millennium – 21st
Century (163)
Bacteria culture
The legacy of the
Scientific Revolution,
modern medicine depends
on observation and
experiments for diagnosis.
The science of preserved food
Sir Francis Bacon was a
lawyer and philosopher.
Once, he was also put in
debtors’ prison for
owing people money.
He is best known for an
experiment he carried
out to see if snow could
preserve meat. In
March 1626, while he
was stuffing a chicken
with snow, he caught
pneumonia. He
died on 9 April
1626, a martyr
to science.
151
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World History
The American Revolution and Civil War
The American Revolution and the Civil War were two of the
most important events in the history of the United States. The
Revolution established the United States as an independent and
democratic country. The Civil War was fought to gain equality
for all by abolishing slavery. The United States of America
became an example of enterprise and justice.
Q Why did Britain and France clash
in North America?
A By the eighteenth century, word
Battle of Bunker Hill
This battle on 17 June 1775
may have seen the
maximum casualties during
the American Revolution.
Quick Q’s:
1. Which thirteen
colonies formed the
original United States
of America?
New Hampshire,
Massachusetts, Rhode
Island, Connecticut,
New York, New Jersey,
Pennsylvania,
Delaware, Maryland,
Virginia, North
Carolina, South
Carolina, and Georgia
were the original
thirteen colonies of the
United States.
2. When did the USA
get its Constitution?
The Constitution of
the USA was adopted
in March 1789.
3. How bloody was the
Civil War?
More than 600,000
lives were lost and
property worth $5
billion was damaged
during the Civil War.
152
of North America’s wealth had spread
throughout Europe. France called its colony
in the north New France. The British settlers
came by the shiploads. They colonized the
south. Their colonies grew fast. In Europe,
Britain and France were fighting the Seven
Years’ War and so tensions were high between
the two countries. Eventually, the British
defeated the French. A treaty was signed in
1763, which gave the British control over all
of North America except Québec.
Founding father
Benjamin Franklin
(1706–1790) played a key
role in the American
Revolution. He was in
the team that drafted
the Declaration of
Independence. He was
the ambassador to France
and made sure that
this transatlantic
ally supported the
American Revolution.
Q What was the Declaration
of Independence?
A On 4 July 1776, representatives of the
thirteen colonies met in Philadelphia and
declared independence. Britain was not
happy and refused to give up such profitable
colonies. The War of Independence began.
Fierce battles were fought right up until 1783.
George Washington led the Continental
Army, which finally defeated the British.
Q Why did the colonists in the United
States want to be independent of Britain?
A After the end of the Seven Years’ War,
the British government demanded heavy
taxes on imports and trade items – which
included sugar, indigo dye, wine, coffee,
textiles, paper, glass and tea. The colonists
protested. Even pamphlets, newspapers and
playing cards were to be taxed. Britain also
refused the United States permission to print
their own currency notes. The colonists
wanted more political freedom. This led to
riots. On the night of 16 December 1773,
about fifty colonists disguised themselves
as Mohawks and raided three British ships
anchored in Boston harbour. They dumped
342 containers of tea, which was taxed
heavily, into the sea. This act of defiance
was known as the Boston Tea Party and
started the Revolution.
The life of a slave
Slaves were worked hard, fed little and treated cruelly.
Many who tried to escape were caught and punished.
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The American Revolution and Civil War
Q What was the Civil War?
A The American Civil War was fought
between the US government and eleven states
in the southern United States who refused
to give up slavery. These eleven states called
themselves the Confederate States. The war
started in 1861 when the president of the USA
Abraham Lincoln declared that slavery would
be ended and the Confederates decided
to break away from the USA in protest.
Q Which were the states that formed
the Confederates?
The Loyalists
The Loyalists were faithful to Britain during the American
War of Independence. They believed they owed loyalty to
Britain and fought the rebels. Historians estimate that about
20 per cent of the white population in the thirteeen states were
Loyalists, though exact numbers are difficult to come by.
After the Declaration of Independence in 1776 the Loyalists
were regarded as traitors. As a result, many of them changed
their allegiance. But many of those who remained Loyalists
were exiled and lost their land and possessions. Between 1775
and 1783, over 70,000 Loyalists were forced out of the United
States. Of them, 50,000 went north to what is now Canada.
These Loyalists called themselves the United Empire Loyalists.
A few other Loyalists returned to Britain and many settled in
other British colonies like the Bahamas.
A South Carolina was joined by Florida,
Mississippi, Georgia, Texas, Alabama,
Louisiana, Tennessee, North Carolina,
Virginia and Arkansas. Most of the states
were controlled by slave-owners. They
formed the Confederate States of America.
Q How did the Civil War end?
A The Federal army, made up of the
northern states, won after four years of fierce
fighting. The Confederates surrendered on
9 April 1865. Lincoln was assassinated by
a Confederate supporter just five days later.
Federalists
Loyalists
Marching to war
Union soldiers marching
to join the Civil War and
ensure that the United
States of America
remained one country.
The Civil War witnessed
very heavy casualties
on both sides. The
Confederates registered
some victories in the
beginning. But the betterequipped Federal forces
prevailed at the end.
Try these too…
North America
(110–111), The British
Empire (146–147)
153
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World History
The French Revolution
The French Revolution, which lasted for ten years from 1789
to 1799, changed the entire political system and society of
France. Before the Revolution, the king held all the power.
The Revolution transferred this power to the citizens, who
ruled through a governing body. The effects of the French
Revolution were felt across most of the world.
Quick Q’s:
1. Who was
Robespierre?
Maximilien
Robespierre was an
important leader
during the French
Revolution. He was
part of the Commune
of Paris that overthrew
Louis XVI. Under his
orders, protesters were
paraded and
guillotined in public.
On 28 July 1794,
Robespierre himself
was guillotined without
a trial.
2. Did Marie Antoinette
really ask the people to
eat cake?
When there was a
shortage of bread in
Paris, the queen Marie
Antoinette is believed
to have said, ‘If they
have no bread, then let
them eat cake!’ There
is no evidence of this.
3. Why was the
storming of the
Bastille important?
It was the first open
rebellion against the
king. While most
people know that
prisoners were set free,
few know that there
were only seven
prisoners in the Bastille
at that time. The event
of 14 July is still
celebrated in France as
a national holiday.
154
Q What led to the French Revolution?
A The French Revolution had been
building up for years. The king of France
at the time was Louis XVI. He was young
and inefficient as a king. A long, hard winter
had killed most of the crops and lots of
people were unemployed. The king was
spending huge amounts of money on wars
so taxes had to be raised. The majority of
people were getting poorer and poorer while
the rich were living it up. At around this time,
the Age of Enlightenment was in full swing.
Philosophers were becoming interested in
equality, human rights and liberty for
everyone. These philosophers encouraged
scientific thought and looked down upon
the old traditions held in place by the king.
The people became passionate about these
ideas and rose in protest.
Q Was it only the poor who revolted against
the king?
A Almost all the classes were against the
King. France was teeming with 25 million
people, the largest population in Europe.
Most were starving peasants. Paris was
crowded with merchants, traders and factory
workers, all seeking more power and
privileges from the king. The clergy (priests)
held 10 per cent of the land, but many parish
priests were very poor, so they supported the
Revolution too. The middle classes supported
it because they wanted more say in elections.
Q How did the Revolution break out?
A On 14 July 1789, an angry mob stormed
the Bastille prison in Paris, set the prisoners
free and started the Revolution. The National
Assembly was taken over. On 26 August 1789,
the Assembly published the Declaration of the
Rights of Man and of the Citizen, which gave
equal rights and freedom to all Frenchmen.
It abolished the old system of land ownership
and changed the justice system.
Storming of
the Bastille
A crowd of people
stormed the Bastille
prison near Paris and
effectively started the
French Revolution.
The event was of
enormous symbolic
significance, because it
was first open act of
rebellion against the
king. After storming the
prison and freeing the
seven prisoners, the
attackers concentrated
on looting the large
quantities of arms and
ammunition stored
there, including over
13,600 kilograms (30,000
pounds) of gunpowder.
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The French Revolution
Q What happened to King Louis XVI?
A At the start of the Revolution, the
Q What was the Reign of Terror?
A The Reign of Terror lasted from
Emperor Louis XVI was forced to move from
his palace in Versailles to Paris. The rulers
of Austria and Prussia sent soldiers to support
Louis and help him to escape. But he was
captured and returned to Paris. In August
1792, Louis XVI was forced to step down
from the throne, his family was imprisoned,
and France was declared a republic. In
January 1793, Louis XVI and his wife,
Marie Antoinette, were beheaded. Many
other noblemen who had sided with the
royal family also lost their lives in the French
Revolution. Some fled to other countries and
worked against the new government.
5 September 1793 to 28 July 1794 when over
20,000 people opposed to the Revolution were
killed. The Reign of Terror effectively ended
a day after two of its most important leaders,
Robespierre and Marat, were killed themselves.
Try these too…
Napoleonic Wars
(156–157), The World
Wars (158–159)
The guillotine
The guillotine (seen here)
was the killing machine of
the Reign of Terror.
Q What was the effect on the people?
A The Revolution did not improve the life
of the poor. Food was still scarce and there
was rioting. The days of the week were
renamed and a new calendar was adopted,
which caused chaos. Churches were closed.
With no king and a sudden change in
government, there was confusion about
who was in charge. Several ambitious people
fought for power. Those who lost were
beheaded. And so began the Reign of Terror.
The philosopher
Jean-Jacques
Rousseau (1712–1778)
was one of the
philosophers whose
political theories
led to the French
Revolution. He was
also well known as
an author and music
composer.
The killing machine
The guillotine was a machine used for
executing prisoners by chopping
off their heads. The first known
guillotine-like instrument
was used in 1307. However,
it wasn’t until the French
Revolution that it became a
common way to kill people.
It was named after a French
doctor, Joseph-Ignace Guillotin
(pictured), who
recommended it
as a more humane
way to execute
prisoners than the
other methods of
the time. At least
20,000 people were
executed by the
guillotine during the
French Revolution.
155
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World History
Napoleonic Wars
Napoleon Bonaparte or Emperor Napoleon I of France
conquered almost all of Europe before being defeated by the
British. Napoleon received the biggest compliment any army
officer could hope for, when his arch enemy, the Duke of
Wellington, called him the greatest general ever. He changed
for ever the way wars were fought.
Royal resting place
Napoleon’s tomb in Les
Invalides in Paris.
Quick Q’s:
1. Did Napoleon
inspire other leaders?
Napoleon has inspired
many leaders. He
didn’t hesitate to take
a tough decision, even
if it meant destruction.
He never accepted
a treaty that gave
him less than what
he thought war
could get him.
2. Where is
Napoleon’s throne?
Napoleon’s red and
gold throne is kept
in the Louvre
museum in Paris.
3. How did
Napoleon die?
The causes of
Napoleon’s death are a
mystery. Some people
believe he died of
arsenic poisoning, and
others say he suffered
from cancer of the
stomach, like his father
before him.
156
It gave Napoleon power over most of
northern Italy. The Italian campaign was one
of his greatest, during which he captured
160,000 prisoners and 2,000 cannons. His
military success made him a popular political
figure in France.
Q Who was Napoleon?
A Born on 15 August 1769 in Corsica,
Q Where did he go after that?
A Napoleon spent 179–99 trying to
Napoleon rose to power as a general during
the French Revolution. He became the First
Consul – the virtual ruler of France, on 11
November 1799. In May 1804, he took the
title of Emperor Napoleon I.
conquer Egypt, which was then a part of
the Ottoman Empire. Napoleon wanted to
protect French trade interests in Egypt and
to provide an obstacle to Britain’s access to
India. He reached Alexandria on 1 July.
Napoleon gained the upper hand on land,
and the many scientists who had gone with
the military expedition made a number of
discoveries. This included the finding of the
Rosetta Stone, which enabled scholars to
read the ancient Egyptian script. But the
British Navy, under Admiral Horatio Nelson,
captured all but two of his ships in the
Mediterranean. Napoleon returned to Paris
in 1799, leaving his troops in Egypt. The
British now defeated the French troops, who
were sent back to France in British ships.
Q Why is his Italian campaign so famous?
A In 1796, Napoleon led the French troops
in an invasion of Italy. A true General, he
mingled with his soldiers and won their trust.
He defeated the Pope’s army and took over
some of the papal land. The following year,
he took Pope Pius VI prisoner, and the Pope
died in captivity. The Treaty of Campo
Formio with the Italians was made in 1797.
Napoleon’s Waterloo
The battle of Waterloo
took place on 18 June
1815 at a site in today’s
Belgium. This was
Napoleon’s last battle,
where he was finally
defeated by the allies.
The Duke of Wellington
led the British forces in
battle, while the Prussians
were led by Gebhard
Leberecht von Blücher.
The battle raged for most
of the day without any
side being able to get the
upper hand, until the
British forces withstood a
final French attack in the
evening and the Prussians
broke through Napoleon’s
right flank.
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Napoleonic Wars
Q What did Napoleon do after Egypt?
A Following the Egyptian campaign,
Q How did Napoleon’s reign end?
A While Napoleon was away on the Russian
Napoleon set his sights on political power at
home. He seized control of the ruling council
in France in November 1799. In 1804 he
drafted the Code Napoleon, covering virtually
every subject from the church to the military,
education and government. Some of the
suggestions from the Code are still followed
in many countries. In 1804, Napoleon also
became Emperor of France. There were
several battles over the next eight years.
Napoleon continued to be the most powerful
general in Europe, forcing treaties on
Austria, Britain, Russia and Prussia. His
greatest victory was at Austerlitz in 1805,
when he defeated the joint forces of the
Russian and Austrian empires. The battle
is often considered a masterpiece of war
strategy and tactics on the part of Napoleon.
campaign, his enemies in Europe became
strong once again, and grouped together to
remove him. By 1813, Napoleon knew he was
in a tight spot. Even the British had reached
France. Now, the people of France lost
confidence in him. On 30 March 1814, Paris
surrendered to the allied forces of Britain,
Russia, Prussia and Austria. Napoleon
stepped down from the throne of France. He
was exiled to the Mediterranean island of
Elba. But Napoleon still had many supporters
in France, who continued to work for his
return. In 1815, just 11 months after being
imprisoned in Elba, Napoleon escaped to
France and regained his throne. But his
enemies in Britain, Russia, Prusssia and
Austria would not accept Napoleon as
emperor. After several more battles, he was
defeated at Waterloo on 25 June 1815. This
time, Napoleon was exiled to the island of
St Helena in the Atlantic Ocean. On 5 May
1821, at the age of 51, Napoleon died while
in captivity. But well after his death, the
legacy of Napoleon continued, especially in
the area of military strategy.
Q Did Napoleon conquer Russia?
A In 1812 Napoleon turned on Russia with
a huge army of over 400,000 soldiers. To keep
such a large force on its feet, he needed
another 400,000 people who provided food,
clothing, tents and so on. Rather than face
Napoleon’s troops, the Russians chose to
retreat. As they moved back, they destroyed
crops and resources so that the French army
would not find any supplies to plunder.
The French reached Moscow on 8 September
after the Battle of Borodino. It was one of the
bloodiest battles of that age, killing 80,000
soldiers on both sides. But the Russians
refused to be defeated. They would rather
destroy their own land. So, they set fire to
Moscow. Napoleon could do little but retreat.
Crippled by the lack of food, the French
army lost thousands of men to disease. As
winter set in, Napoleon’s Grande Armée was
also up against the extreme cold of Russia.
By the end of 1812, only 10,000 of the
original 400,000 soldiers survived. It was
a major blow to Napoleon.
Try these too…
Europe (116–117), The
French Revolution
(154–155), The World
Wars (158–159)
Admiral Nelson
The British Admiral
defeated the French Navy
in the Mediterranean and
did not allow any supplies
to reach the French troops
in Egypt.
A matter of inches
Napoleon is said to have been
one of the shortest generals
in history. For years people
believed that his height was
just 1.58 metres
(5 feet 2 inches).
However, what most
historians forgot
was that Napoleon’s
height had been
measured in French
units. When converted to
Imperial units, this is 1.69 metres
(5 feet 6.5 inches). His personal
guards were part of an elite force of
very tall soldiers. This also made him
look smaller than he was.
157
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World History
The World Wars
The two World Wars took millions of lives. In the 31 years
from the beginning of World War I to the end of World War II,
the world changed in a more fundamental way than it had in
the hundreds of years before that. New nations were created
and old nations were divided by the political interests of
powers thousands of kilometres away.
Quick Q’s:
1. What was
the blitzkrieg?
The Germans
introduced a new and
effective military
operation during
World War II. The
blitzkrieg was a quick
and strong surprise
assault on the enemy,
using a combination
of tanks, aircraft
and motorized
infantry vehicles.
2. Did Germany
surrender after
World War II?
Germany surrendered
just eight days after
Hitler shot himself on
30 April 1945.
3. What was
the Bismarck?
On 24 May 1941, the
British battle cruiser
Hood was sunk by the
German battleship
Bismarck near
Greenland. The British
chased the Bismarck
across the Atlantic and
sank it on 27 May.
4. What was the SS?
The SS or Schutzstaffel
(Defence Staff) was
Hitler’s personal army.
The Gestapo or Secret
Police was a part of it.
The SS were also in
charge of the Nazi
concentration camps.
158
Q What led to World War I?
A World War I was fought between 1914
and 1918. It was the longest, costliest and
most violent war the world had seen. It
involved most European countries and the
United States. In the nineteenth century,
growing overseas colonies and trade rivalries
led to intense nationalistic feelings
throughout Europe. The Industrial
Revolution led to a need for more and more
raw materials. Once the goods were made,
their makers needed new markets to sell these
goods to, and countries rivalled each other
for markets. Each country built up a large
army to safeguard its interests and to strike
fear into its opponents.
Q Did anyone think of peace talks?
A There were attempts to defuse the
situation at the Hague Conferences of 1899
and 1907. But they had little effect.
Fearing war, Germany, the Austro-Hungarian
Empire and Italy formed the Triple Alliance.
D-Day
In World War II, the Allied forces carried out a major
invasion of German-held France from the area of
Normandy in 1944.
On the other side, Great Britain, France
and Russia formed the Triple Entente.
Germany supported Morocco’s independence
from France in 1905–6. There was more
tension when Austria-Hungary took over
Bosnia and Herzegovina in the Balkans in
1908. On 28 June 1914, Archduke Francis
Ferdinand, heir to the Austrian and
Hungarian thrones, was assassinated in
Sarajevo, Bosnia by a Serb called Gavrilo
Princip. It was this act that sparked the war.
Q What were the trenches?
A Very early during the course of World
War I, the armies found out that with new
weaponry, they could dig even a shallow hole
in the ground and stop the advance of the
enemy. That was why both Germany and the
Allied powers (mainly Britain and France)
started digging trenches in the ground, where
their soldiers could stay and defend their
territory. As the war went on, the trenches
became deeper and more complex.
Trench warfare
World War I saw the large-scale use of trenches for the
first time. The area between the trenches of the
opposing armies was often filled with barbed wire to
make an enemy advance even more difficult.
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The World Wars
Q How long did the peace last after World Q How did the Second World War end?
War I?
A The war in Europe ended in 1944, but it
A In 1918, World War I finally came to an continued in Asia. President Harry Truman
end. In 1919, the Allies – the United States,
Britain, France and Italy – worked out the
Treaty of Versailles. But the peace did not last
long. In 1933, the Nazi leader Adolf Hitler
came to power in Germany. He promised to
make up for the defeat of Germany in World
War I. In 1935, Hitler defied the Treaty of
Versailles and began building up an army.
Germany began a military campaign, taking
over Austria and a part of Czechoslovakia. On
1 September 1939, Germany attacked Poland.
On 3 September, Britain and France declared
war on Germany and World War II began. It
was even fiercer than World War I. The Allied
Powers included Britain and its colonies, and
the Soviet Union and the USA. Germany,
Italy and Japan formed the Axis powers.
Battles took place across the world.
Q What were the consequences of
World War II?
A Over 62 million people, or 2.5 per cent of
the world’s population, died in World War II.
Eight out of every ten deaths were on the
Allied side. The Soviet Union lost at least 23
million people. People around the world died
of disease and starvation caused by the war.
Adolf Hitler unleashed racial hatred against
people who were from other races or
religions. Two-thirds of his victims were Jews.
Hitler’s Nazis began by shooting thousands of
Jews. Later, they built death camps where
people were shot or gassed or simply allowed
to waste away. Chemical weapons were used
in this war as never before. Under orders
from Emperor Hirohito, Japan used toxic gas
375 times. Thousands of British, Australian
and other Allied troops died in the harsh
conditions of the Japanese prisoner
camps. The political map of the world was
completely changed by the war – it led
to the end of colonialism.
of the USA ordered the world’s first atomic
attack. On 6 and 9 August 1945, two atomic
bombs were dropped on the Japanese cities of
Hiroshima and Nagasaki, killing thousands
and injuring thousands more. Japan
surrendered on 14 August 1945.
Try these too…
North America
(110–111), Europe
(116–117), Asia
(120–121), The
World after World
War II (160–161)
Enola Gay
The B-29 Superfortress
that dropped an atomic
bomb on Hiroshima.
Pearl Harbour
Pearl Harbour is in Hawaii. It was one of the important military
bases of the United States of America. On 7 December 1941,
Japanese submarines and aircraft attacked the US Pacific fleet at
Pearl Harbour. Eight American battleships and thirteen other
naval vessels were sunk or badly damaged. Nearly 200 American
aircraft were destroyed. About 3,000 military personnel were
injured or killed. It was this attack that brought the USA in to
World War II on the side of the Allies.
159
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World History
The World after World War II
When World War II ended, almost everyone, everywhere, had
been affected by it. Maps were redrawn, and people living in
the new territories were suddenly thrown into new societies.
Old countries ceased to exist.
Quick Q’s:
Q What was the most important task after
1. Why was the United
Nations Organization
formed?
World War II ended?
The Allied nations got
together after World
War II to form the
United Nations in
1945. An organization
of all countries, it is
meant to prevent wars
and to help in overall
development around
the world.
A Millions of people had lost their lives.
Millions more had fled their home countries
as refugees. Countries had lost most of their
money buying arms and keeping huge armies
fed and clothed. Industries had been bombed
out and had to be rebuilt. Most countries
spent the second half of the twentieth century
trying to rebuild what was lost.
A modern assembly line
Assembly lines in modern factories have improved
efficiency. In a modern car factory, most of the work
consists of assembling parts made by others.
Q How did the spread of liberal ideas
change the world?
2. Why do people fight
over oil?
Q How has modern science affected
A Ideas of liberal democracy spread around
With more automated
transport like cars,
buses, trains and
aircraft being used,
more and more oil is
required. Vast oil fields
were found in the
Middle East which the
Western world needs to
use to maintain their
current lifestyle. Oil
has become the cause
of world-wide conflict.
everyday life?
the world after World War II, partly as a result
of the Allied victory in the war. The first result
was that colonies of European powers started
to demand their freedom, and most of them
had gained independence by the 1960s. Also
during the 1960s, there were protest
movements by some American and European
university students against the involvement of
the USA and European countries like France
in the Vietnam War. The liberal ideas of these
youth leaders gave rise to large-scale anti-war
movements around the world. New forms of
music pioneered by bands like the Beatles
helped these ideas to spread, leading to a
sense of rebellion against the establishment
and traditional society. This had a far reaching
impact in many countries – attendance in
churches declined and
age-old social
institutions such as
marriage lost a lot of
their significance.
3. Why do we need to
look for new fuel?
The supply of oil and
coal is limited. We
need to look for new
fuel sources that are
renewable, so that
there can be no risk
of running out of fuel.
Scientists are studying
various renewable
sources of energy such
as solar power, wind
power and biogas to
reduce the cost of
producing usable
energy from these
sources.
160
A The World Wars inspired scientists to
think of bigger and better machinery. All
wars fought after World War II have used
more machinery and fewer humans. Since so
many people had died in the World Wars,
scientists wanted to develop machines that
would take over much of the work. Also, after
World War II, factories began producing
cheaper goods in larger numbers. This
changed transportation. From animal-drawn
carriages, which had been the only land
vehicles for thousands of years, trains, cars
and aircraft became common. Space studies
also improved, originally for military reasons.
Within 25 years of World War II ending,
man had landed on the moon. Wired
communication and signalling like Morse
code and semaphore were not used any
more. Satellites speeded up communication
and personal computers connected millions
of homes to the Internet. Machines such
as washing machines, dishwashers, vacuum
cleaners and microwave ovens speeded up
household work.
Bringing social change
Musicians like Bob Dylan
(left) have influenced
modern society greatly.
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The World after World War II
Q What was the Cold War?
A At the end of World War II, the
victorious Allied countries found themselves
divided into two distinct camps – one led by
the USA and the other by the former Union
of Soviet Socialist Republics (USSR). As the
USA and the USSR had both started to make
many nuclear weapons, the tension between
the two camps became a matter of concern
all around the world. The USA and the USSR
fought through other countries – in Korea,
Vietnam and Afghanistan. Both superpowers
tried their best to include more countries in
their camps. But they did not go to war
against each other directly, which was why the
state of affairs was described as a Cold War.
The Cold War lasted till 1990, when the
USSR collapsed into a number of
independent countries and most of the
countries in this camp chose to move
towards a system of liberal democracy.
Q What was apartheid?
A Apartheid was established in 1948 by
the South African government, run by
descendants of European settlers. This was a
regime in which black South Africans did not
have the same rights as the whites and were
treated very unfairly. In 1994, the fight
against apartheid succeeded and Nelson
Mandela became the first non-white
President of South Africa.
Modern messiah
Nelson Mandela, a leader
of the African National
Congress, spent 27 years
of his life in the infamous
Robben Island prison
on an island off the Cape
of Good Hope for his
opposition to apartheid.
But on becoming the
President of South Africa,
he implemented a policy
of reconciliation with
supporters of the earlier
apartheid regime.
Q Did human health improve in the
twentieth century?
A
New medical research during the
twentieth century has helped people in many
ways. Surgery has improved and organs
including the heart, liver and kidneys can
now be transplanted, so that the failure of a
vital organ need not necessarily lead to death.
Doctors have become better able to diagnose
problems with improved technologies such as
X-rays and sonograph and various kinds of
imaging of the body and the brain. Doctors
can also examine the health of foetuses
through techniques such as ultrasound
sonography. Antibiotics that followed the
discovery of penicillin now help fight diseases
that earlier killed thousands. Life expectancy
improved in the twentieth century. However,
new viruses like HIV/AIDS are spreading
throughout the world. In the West, where
food is plentiful, obesity (excess fat) has
created new health risks.
The X-ray
Methods of medical
diagnosis have vastly
improved in the years
since World War II. Today,
doctors have many tools
like X-rays, sonography,
magnetic imaging and
so on to look inside the
bodies of their patients,
find out exactly what has
gone wrong, and treat
the patients accordingly.
Try these too…
The World Wars
(158–159), The New
Millennium – 21st
Century (163)
A telly in every home
The period after World War II saw major developments in
broadcasting through television, though it had started before
and during the war years. The first colour broadcast on network
television took place in the USA on 25 June 1951. Since then,
the availability of satellite communication has made it possible
to watch ‘live’ television programmes from around the world.
The number of television channels has increased many times.
Television receiver sets have also improved and new technologies
like liquid crystal display and plasma display have been developed.
An old (left) and a new (right) TV receiver set are shown here.
Towards the end of the twentieth century, television programmes
started to be distributed over the Internet.
161
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World History
Computer Revolution
The Industrial Revolution made work so much faster that people
needed machines to help them keep track. Adding machines and
cash registers helped them. Modern wars also required arms,
ammunition and plans that were more precise than ever.
Governments needed efficient and safe machines to store and
process information. The computer was the answer.
The familiar mouse
The mouse makes it easy
to select the item that we
want to use on screen. It
was named the mouse
because the thin wire that
connects it to the
computer looks like the
tail of a mouse.
Q What were the very first computers like?
A The first mechanical computer was
Data carriers
Compact disks can carry
data between computers.
Quick Q’s:
1. Who was Grace
Hopper?
Grace Murray Hopper,
nicknamed Amazing
Grace, worked on the
Harvard Mark I
computer. She coined
the term ‘bug’ for a
computer fault,
because a moth had
led to a fault in the
Mark I. She was also
the first person to
debug a computer.
2. What was the first
computer game?
The first computer
game, called Spacewar,
was invented in 1962.
It was a two-player
game. Each player
controlled a spaceship
and fired at each other.
3. Who invented the
floppy disk?
A team of IBM
engineers led by Alan
Shugart invented the
floppy disk in 1971.
162
invented by Wilhelm Schickard in 1623. It was
a calculating machine that could add and
subtract six digit numbers. Charles Babbage is
known as the father of computing. He
designed the Difference Engine, which could
calculate tables. In 1833, he invented the
Analytical Machine, which could add in three
seconds and multiply and divide in two to
three minutes. Konrad Zuse, a German
engineer, is called the inventor of the modern
computer. He built automatic calculators that
had memories and could show him the results
of previous calculations. In 1936, he made Z1,
a machine with a control, a memory, and a
calculator. It was the first binary computer,
which means it used the numbers 0 and 1 to
carry out its calculations. Today’s computers
are all binary – everything is finally translated
to 0 and 1 for them. In 1941 Zuse also made
Z3, the world’s first electronic, fully
programmable digital computer.
Q What was the 4004?
A In 1971, scientists in Intel made the
first single chip microprocessor. It was called
Intel 4004. This put the central processing
unit, memory, input and output controls
on to one small chip. The development
of personal computers became easier due
to the chip. The first personal computer
was sold in March 1974. The number of
PCs multiplied many times in the 1990s
with the development of the Internet.
Q What is the Internet?
A The Internet is a worldwide network that
is accessible to all computers with an Internet
connection. This network allows computers
from all over the world to communicate with
one another, so that users have access to a
bank of information. Now people can
communicate with each other through e-mail
on the Internet. They can also chat, share
music, play with others, show photographs
and write diaries for anyone in the world with
Internet access to read. The Internet has
created a ‘global community’ that was
unimaginable just a few years ago.
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The New Millennium – 21st Century
The New Millennium – 21st Century
Despite advances in science, medicine and technology, the new
millennium is not without its troubles. Terrorism, when people
wreak havoc by killing and injuring innocent people, is an
increasing threat. On top of the fear of terrorism, pollution and
global warming are serious threats in the new century. But many
countries also expect to join the developed world in this century.
In memory
Memorial lights of the
World Trade Center,
whose twin towers were
destroyed by terrorists.
Thousands of people were
killed by the terrorist act.
Q Did the new millennium bring
Q Why is the twenty-first century called the
countries together?
Age of Terrorism?
A In 2002, the euro became the common
currency of some of the member countries in
the European Union. In 2007, the number of
members rose to 27 countries. Meanwhile,
other countries gained their independence.
East Timor in Southeast Asia became the
youngest nation in the world when it gained
independence from Indonesia on 20 May 2004.
Q Has the world become warmer in the
twenty-first century?
A Increasing use of fuel for industry and
transport is warming up the Earth. As a
result, natural disasters have become more
frequent and more deadly. On 26 December
2004, an earthquake and tsunami in the
Indian Ocean killed over 310,000 people in
many countries. On top of such disasters, the
amount of ice at the North and South poles is
decreasing due to global warming. So sea
levels will rise and swamp coastal areas all
around the world, according to scientists.
Wind power
Using traditional
power sources
such as coal and
oil is adding to
pollution. Cleaner
ways to produce
energy like
windmills are
now becoming
more and more
popular around
the world.
A
On 11 September 2001, nineteen
terrorists hijacked four passenger airplanes in
the United States. They flew American
Airlines Flight 11 and United Airlines Flight
175 into the twin towers of the World Trade
Center in New York. Another aircraft hit the
Pentagon building in Washington. The
passengers and crew of United Airlines Flight
93 attacked the hijackers and saved many lives
when the plane crashed into a field instead of
a public building. Almost 3,000 people were
killed in the attacks. George Bush, the
President of the United States, declared a war
on terror that took American troops to
Afghanistan and Iraq. Since 2001, terrorist
attacks have occurred in other cities around
the world. Bombs are detonated in busy
market places and city centres, killing
innocent people. Terrorism is particularly bad
in the Middle East, where Israel has been
fighting most of its neighbours for many
years, and in Iraq. With an increasing clash
between Western and Islamic lifestyles, many
people talk of an Age of Terrorism.
Try these too…
The World Wars
(158–159), The World
after World War II (160161), Communication
and Satellites (192–193),
Air Transport (198–199)
Poor Pluto
Pluto was called the ninth planet of our
solar system since its discovery by Clyde
Tombaugh in 1930. But on 25 August
2006, the International Astronomical
Union said it was not a planet, but a
dwarf planet. Changes like this show how
astronomy is becoming more accurate.
163
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Art and Culture
Architecture
Architecture is what goes in to designing a building. It can
influence anything from a tool shed to a monument like the
Taj Mahal. Architects also design buildings such as the Taipei
101 Tower in Taiwan, which stands 509 metres (1,670 feet) tall
and was the tallest completed structure in the world in 2006.
Quick Q’s:
1. Why is the
Parthenon famous?
The Parthenon was a
temple to the Greek
goddess Athena. It was
built between 447 and
433 BC and still stands
at the Acropolis in
Athens. Its decorative
sculptures made of
white marble make it
an example of the best
Grecian architecture.
2. What is Stonehenge?
Stonehenge, built
between 3000 and 1500
BC, is the best known
prehistoric stone
structure in England.
It is formed of tall
standing stones, or
megaliths, set in a
circle within even older
earthworks. It has been
declared a World
Heritage Site.
Stones in a circle
Modern scholars believe
Stonehenge was an
ancient observatory,
used for predicting
phases of the Moon.
164
Q Have the earliest buildings lasted?
A The earliest buildings were of bark,
leaves, mud and straw. They did not last
long. But later, people began to build temples
and palaces of stone. The earliest structures
that we know of were built in about 9000 BC
in the Neolithic or New Stone Age. These
include the world’s oldest stone temple, the
Gobekli Tepe, in Turkey. Around 7000 BC
the Sumerians, Assyrians and the Egyptians
made huge improvements in building.
Some of the most remarkable early buildings,
including Sumerian ziggurats (temples)
and the Egyptian pyramids, were
made around 3000 BC. As
people grew more confident in
architecture, the buildings
got bigger and more decorative.
Building a cathedral
Stones unloaded by boats for the making of a cathedral
were raised through a system of pulleys. They were
dressed by expert stonemasons before being put in place.
Q What were medieval buildings like?
A With the spread of Christianity, some
of the best medieval architecture was seen
in churches. Churches were built in two
styles: Romanesque and Gothic. The
Romanesque style typically used brick
vaults and rounded arches. Gothic churches
like the Salisbury Cathedral in England
and Notre Dame de Paris in France are
tall churches with pointed-arch windows
and doorways. They are supported by
buttresses and they have beautiful stainedglass windows to let light in. During the
Renaissance, architecture was inspired by
the classical age of Greece and Rome.
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Architecture
Q How did modern architecture
come about?
A
The Industrial Revolution gave architects
many new materials to build with, like iron
and steel, concrete and strong glass. In 1779
English ironmonger Abraham Darby built
the first iron bridge over the river Severn.
It proved that cast iron could be used as
a strong building material. The Crystal
Palace that Joseph Paxton put up at the
Great Exhibition in London in 1851 was
entirely made of glass and iron. Modern
architecture became widespread in the
twentieth century. It was much simpler than
the ornamental style of the past. Buildings
were more practical and designed to make
the most of space.
Q Where was the first skyscraper?
A In the United States, tall buildings were
called skyscrapers as early as the 1880s. They
were built on a steel structure and had central
heating, electrical pumps and lifts. In 1890,
Major William Le Baron Jenney and Louis
Sullivan built the first skyscraper in Chicago.
This was the Home Insurance Building. It
had ten floors, including the basement. Two
floors were added in 1891. Skyscrapers could
house so many people that they changed
the way people lived and worked.
Q What is different about architecture now?
A In contemporary architecture, the
materials often decide the design. There is
little decoration. It is simple and uncluttered
and often, the supporting pillars and beams
are shown. Reinforced concrete and steel
allow architects to use fewer columns, beams
and thick walls. This means that buildings can
now be lighter and taller. Modern buildings
often use glass walls, which allow more heat
and light inside. The latest trend among
architects is to design buildings where the
need for heating and lighting is minimized.
These are called energy-efficient buildings.
Modern city skyline
Modern cities around the
world are dominated by
skyscrapers. Cities like
New York, Hong Kong
and Singapore are full of
them. But there has been
a reaction and in the last
few years low buildings
are being designed again.
Try these too…
Ancient Mesopotamia
(124), Ancient Egypt
(125), Ancient Greece
(128–129), Ancient
Rome (130–131),
Medieval Europe
(136–137)
Touching the sky
The first modern building
The Crystal Palace was built in London’s Hyde Park for
the Great Exhibition in 1851. It was the world’s first
large iron and glass building. After the exhibition, it
was kept in Upper Norwood, where it was destroyed
by a fire in 1936.
The Eiffel Tower was designed
by Maurice Koechlin and made
by Gustav Eiffel. It is 300 metres
(1,000 feet) high. It took 300
workers two years to put together
18,038 pieces of iron with 3.5 million
rivets. It is the tallest structure in
Paris. It was built as an entrance
arch to a world fair held in 1889
to celebrate the 100th anniversary
of the French Revolution.
165
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Art and Culture
Art and Artists
Art is the way people represent themselves and the world
visually. They do this by drawing, painting, sculpture and other
means. The earliest art that we know of are rock and cave
paintings which date back about 40,000 years. The artists used
natural dyes extracted from plants and stones.
Quick Q’s:
1. What is Minimalism?
In the 1950s, Frank
Stella of the United
States painted white
pinstripes on a black
canvas and called it
The Marriage of Reason
and Squalor. When
asked what it meant,
he said ‘What you see
is what you see’. This
style, where painted
objects are not a
symbol for anything
else, is Minimalism.
2. What is pop art?
In the 1960s, American
painters like Andy
Warhol and Roy
Lichtenstein created
art from everyday
objects. They used
soup cans, comic books
and advertisements
to comment on
modern life.
3. What is earth art?
In the 1960s and
1970s, artists like
Robert Smithson used
bulldozers instead
of brushes to create
art from natural things
outdoors. These
works were called
earth art. The earth
art movement was
influenced by concerns
about the deterioration
of the environment
through pollution and
deforestation. The
ideas of the earth art
movement have been
used in movies.
166
Q What were the earliest paintings about?
A The earliest paintings were about things
people did every day like hunting, and about
the wild animals they saw. Horses, bison, deer
and even human hands were drawn. These
paintings were often made with pieces of
coloured stone. The painters were probably
holy men or shamans. Some of these
paintings were of such a high standard that
they were believed to be fakes. When the
Altamira caves in Spain were found and
studied in the nineteenth century, many
people believed the historians themselves
had painted them. The first sculptures also
date back to the prehistoric age. One of the
most famous statues is the stone image of a
woman, named Venus of Willendorf
(Austria). It was carved 22,000 to 24,000 years
ago.
Q Did different ancient civilizations have
The ancestor of all artists
A cave painting in Brazil shows life as it used to be.
The painter used colours made from vegetable dyes.
carving and painting on walls.
How was art important during the
Middle Ages?
Q
A Art and sculpture of the Middle Ages
can be divided into the Romanesque period
and the later Gothic period. The spread of
Christianity meant that more churches were
built. These churches were decorated with
images from the Bible. To show their respect
for God, painters used a lot of gold colour,
made out of real gold. While statues from
the Romanesque period are still around, little
of the fresco art survived. Gothic art gained
ground gradually. Art was also used to
decorate hand-written books.
A Each ancient civilization, including
Q Did the Renaissance affect art?
A The Renaissance, lasting from the
Egypt, Mesopotamia, China, Greece, Rome
and India, had its unique art style. Art was
used for worship, but it also came to be seen
as a form of beauty. Paintings of Egyptian
gods and goddesses covered the insides of
pyramids. The Mesopotamians covered the
walls of their temples with paintings. The
Greeks studied the human body closely, and
their paintings and sculptures include details
of muscles and proportion. The Chinese were
among the first to paint on paper and used
painting to develop the script for the Chinese
language. Indian artists were highly skilled at
fourteenth to the sixteenth century, was a great
period for artists and sculptors. Much of the
inspiration came from the temples and statues
of ancient Greece and Rome. Renaissance
artists believed in the importance of the
human being. They explored the human
form and captured scenes from things around
them. They learnt about perspective, or the
importance of size and distance in a painting.
They painted landscapes and developed new
styles as well as new material to paint with. The
invention of oil painting meant that pictures
lasted far longer without fading.
their own art?
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Art and Artists
Q How did art change in the
Moving masterpieces
nineteenth century?
Michelangelo (1475–1564) was an Italian
painter, sculptor and architect during the
Renaissance. He was a master of
technique. The Pieta, a sculpture of Mary
with the dead Christ in her arms, took him
three years to finish. It was completed in
1500 and stands in Saint Peter’s Basilica
in Vatican City. Michelangelo was just 25
when he finished this masterpiece. His
next major sculpture was the statue David
(see right). Perhaps the greatest honour
for him was to build the tomb for Pope
Julius II, for which he made a statue of
Moses. Beginning in 1508, he painted the
ceiling of the Sistine Chapel over a period
of four years. In 1534, he painted the Last
Judgement on the wall above the altar of
the Sistine Chapel.
A During the Romantic period in the
nineteeenth century, artists began to use
their work as a form of expression. Like
poets, Romantic artists used art to share
their pain, fear and sorrow through nature
and landscapes. Unlike Renaissance artists,
they did not portray human beings as the
ultimate in perfection. Instead, humans
were seen as imperfect creatures. English
painter JMW Turner and French painter
Eugène Delacroix were two of the most
famous Romanticists. French painters like
Claude Monet captured the wonder of
natural light with soft, swift strokes. He and
his fellow artists like Camille Pissarro, Paul
Cézanne, Edgar Degas, Edouard Manet and
Pierre-Auguste Renoir were deeply moved by
how the same landscape reminded them of
different feelings at different times of the day.
This school of art was called Impressionism.
The Impressionist movement had a major
influence on later artists, and even on music
and literature.
Q What is modern art?
A Art from the late nineteenth and
twentieth centuries is called modern art. It
is made up of a number of art movements.
The twentieth century began with artistic
movements like Cubism, Futurism and
Expressionism. Never before had art of every
form been given such freedom. Artists could
express any feeling through any form of art,
not just painting. The Industrial Revolution,
which reduced man to another machine in
a factory and the violence of the two World
Wars deeply influenced twentieth century
art. The Dada movement of World War I was a
protest against set ideas in society. In the
1930s, the Surrealist movement explored
human psychology. Many Surrealist artists
wanted to show the pain and despair of
those who suffered in the war.
Q Has technology influenced art?
A Artists in Europe and the United States
were influenced by art from other societies.
Paul Gauguin and Henri Matisse were inspired
by Japanese silk-screen prints. Pablo Picasso
tried to show the many views or angles in any
subject. This style became known as Cubism.
Many recent art shows include photography,
film, objects or installations, music and even
voices, along with the paintings.
Try these too…
Ancient Egypt (125),
Ancient Greece
(128–129), Medieval
Europe (136–137),
Mughal India (140), The
Renaissance (142–143)
Earth art
The Spiral Jetty, an
artwork created by
Robert Smithson in Great
Salt Lake, Utah, in 1970.
167
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Art and Culture
Music
Music is a combination of sounds that is usually pleasing to
the ear. It can be produced by a singer, a musical instrument,
a bird or even a wind chime. It is an art form that has been used
in worship, as entertainment or as an accompaniment to dance.
It can express different emotions, from joy to sorrow. Human
beings made music before they could write.
Quick Q’s:
1. What were the first
musical instruments?
The earliest musical
instruments were
probably percussion
instruments that kept
a beat. These were
made of material
ancient man found
easily, such as stones,
branches and animal
bones.
2. Are some musical
instruments really
made of vegetables?
Traditional flutes are
made of reeds and
bamboo. Gourds and
coconuts are dried to
make various string
instruments, as well
as drums and castanets.
Jug bands and skiffle
music use washboards,
metal buckets and glass
jugs. The musician
blows across the
opening of the jug to
make a vibrating noise.
Q What is classical music?
A Music composed between the mid-1700s
and the early 1800s in Europe is called
classical music. This music includes great
detail, showing how every note should be
played. Classical musicians require years of
guided training. Classical music began with
church music and later included music for
the royal court. In other parts of the world,
different countries have their own classical
music. Classical Qin music of China is over
1,000 years old and is played with a sevenstringed zither. In India, classical music is not
written, but is set to basic ‘ragas’ or a pattern
of notes in a scale.
Q Who invented opera?
A Opera is a form of theatre in which
the drama is conveyed through music
and singing. Opera singers develop
special vocal techniques. They are
accompanied by an orchestra. The
musicians are in a pit in front of the
stage. Opera emerged in Italy around
1600 AD. Daphne by Jacopo Peri, written
in 1597, was the first opera production.
The work is now lost. The first
opera that we have today is a 1600
production, also by Peri. It was
called Euridice. The first opera that
is still performed regularly is Orfeo by
Claudio Monteverdi, composed in 1607.
Playing the trumpet
Louis Armstrong was one of the top jazz
musicians of the twentieth century.
168
Superstar
Modern musicians like Bon Jovi (above) have millions of
fans around the world. They also have a major influence
on fashion trends.
Q What is Blues music?
A Blues music grew out of the songs and
chants of the African-American slaves in
the southern United States. This vocal and
instrumental musical style has inspired several
other popular genres like pop, rock and roll,
ragtime, rhythm and blues and jazz. The Blues
get their name from ‘feeling blue’ or sad.
Q How did jazz develop?
A Jazz was also developed by AfricanAmericans around the first decade of
the twentieth century. Jazz, blues and pop
music developed at virtually the same time
and are similar genres of music in many
ways. Blues singers like Bessie Smith, Ma
Rainey, Louis Armstrong and Benny Carter
were also jazz musicians. Jazz is mostly
instrumental and encourages improvisation.
The saxophone, trumpet and trombone
are popular jazz instruments.
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Music
Warbling on
Millions of children have played
the recorder, which is a type of
folk flute. Recorders have six
finger holes and a hole for the
left thumb. Recorders have
been played in Europe since
the fourteenth century. King
Henry IV of England had a
recorder and King Henry VIII
of England had 76. Today,
recorders are often the first
instrument for children to learn
music. They were an important
part in the music of composers
like Bach and Vivaldi.
Q Did science help music?
A Developments in science led to the
Q What is pop music?
A Pop is short for ‘popular’. Popular music
includes music from films and musical
comedies, and even country music and rock
music. The lyrics are often about everyday life.
Country music is inspired by the outdoors: it is
simple and tells a bit of a story. Rock ‘n’ roll
began in the 1950s, inspired by Rhythm and
Blues (R&B). Elvis Presley and Buddy Holly
mixed in blues and country with their own
music to produce yet another genre –
rockabilly. Famous modern music stars include
Bob Dylan, Joan Baez, Eric Clapton, Sting,
Elton John, groups like the Beatles, Queen and
U2, the hard-rock group Deep Purple and the
heavy-metal band Mötley Crüe. Rock music led
to Heavy Metal, a loud style of music in which
the guitar is important. Recent music stars
include Eminem, Beyonce Knowles, Shakira
and the group ‘NSync.
creation of new musical instruments like
synthesizers and drum
machines. Electronic music,
which has been growing
since the 1960s, is played
on these instruments.
Electronic music has given
rise to different styles like
techno and house music.
Rap developed in 1979 from
R&B with rhythmic vocals. It
is recited to electronic drum beats and digital
recordings of other music. Famous rappers
include Eminem and Jay-Z. Hip-hop includes
rap and break-dance. Like rap, it is often
played by the disc jockey (DJ), who mixes
sounds, adds his own electronic effects and
creates new music. Advances in technology
also made music popular and accessible to
wider audiences. The microphone magnified
sound and the gramophone, which came in
about 1910, allowed music to be recorded
and played over and over again. The earliest
records were made of rubber or shellac.
Nowadays, music is recorded on cassettes,
CDs and DVDs and using digital technology.
Portable music
With the development of
digital technology,
personal music players
have become small and
portable. They can record
music from the Internet.
Music sheet
A part of a music sheet
written by the famous
composer Wolfgang
Mozart. Musicians have
to learn how to read the
notations and follow the
score while playing.
Try these too…
The Renaissance
(142–143), Computer
Revolution (162),
Sound (182–183),
Communication and
Satellites (192–193)
169
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Art and Culture
Theatre
The word drama comes from the Greek dran which means
to perform. Drama usually involves actors on stage, performing
a story through dialogue or song. Drama and theatre include
acting, pantomime, mime, opera, musicals and ballet.
Quick Q’s:
1. Why are some plays
staged again and again?
Some plays are so
popular that many
people want to see
them. Life with Father
by Clarence Day Jr
was staged in the USA
about 3,200 times and
Oklahoma by Richard
Rodgers and Oscar
Hammerstein had
2,000 performances.
2. Did European
theatre allow women
performers?
Acting was considered
disgraceful for women,
so even Shakespeare’s
plays had young boys
playing the part of
women. Women
started acting in the
seventeenth century.
3. Which is the longestrunning musical?
The Broadway musical
A Chorus Line was
performed for the last
and 6,137th time on
28 April 1990 at the
Shubert Theatre.
4. What is African
theatre about?
In Africa, traditional
theatre is often not
written, but memorized.
In Nigeria, the story
of Obatala, the
Nigerian creator
god, is played every
year. Entire villages
participate in the ikaki
or tortoise play.
170
Q What is the earliest theatre we know of?
A The first theatre that we know of in
Europe was in ancient Greece. It dates back
to about 600 BC, when a poet named Thespis
won the first drama competition. Theatres
were built outdoors along a hillside that was
cut into steps to seat people. The Greeks
preferred tragedies – sad events, over comedy
or laughter. Some Greek playwrights like
Euripides and Sophocles are still studied and
performed today. About 300 BC, the Romans
began to write plays in Latin. They preferred
comedies. But theatre was not an envied
profession, so they chose slaves to act. The
Romans loved theatre so much that they built
125 theatres in a period of about 200 years.
To make theatre more exciting, their plays
became violent. These Roman theatres were
closed down with the spread of Christianity.
In classic style
Dionysos Theatre below the Acropolis Hill in Athens,
Greece, is typical of the style of ancient Greek theatres.
In this open-air theatre, the audience sits at a level
higher than the stage.
Kabuki theatre
The Kabuki theatre of Japan has changed its form many
times since it started in 1603. In the beginning, women
played the roles of both men and women.
Q Was theatre allowed in medieval Europe?
A The dislike for theatre continued
through the Middle Ages. Theatre buildings
were not allowed, so actors or wandering
minstrels stayed on the move. Soon, acrobats,
jugglers and puppeteers joined them. They
put up simple platforms to serve as stages
wherever they went. They were frowned upon
by the Church. However, Christians began
their own simple form of theatre to explain
the gospel better. Priests acted out events
from the Bible, since not many people could
read. These were known as Miracle plays.
Q When did theatre make a come-back?
A During the Renaissance people began
studying the almost-forgotten ancient Greek
and Roman texts. This led to a new interest
in theatre. One of the new forms was the
proscenium theatre in Italy, with a frame
that divided the stage from the audience
and a painted backdrop to make it more
realistic. In England, the sixteenth century
saw some of the best-ever plays being written
by playwrights like Christopher Marlowe,
Samuel Johnson and William Shakespeare.
In France, playwrights like Molière and
Racine wrote about ordinary people.
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Theatre
Q What is theatre like around the world?
A Kabuki is a form of Japanese theatre that
began in the early 1600s. It was created by a
woman named Okuni. It uses a particular
kind of music and the actors are dressed in
special costumes with thick, colourful makeup that resembles a mask. As something
important happens, the actor stares and
crosses his eyes in a special action. Make-up
colour is important. A good character wears
red and a bad character has blue paint.
Different civilizations of Asia encouraged
different forms of theatre. Asian theatre,
unlike theatre in the West, often combines
storytelling, dance, music, and mime but
may not have a text. Masks, make-up and
costumes are often important. The Peking
opera of China even includes acrobatics. You
know the character by the voice it sings in.
A series of globes
The original octagonal Globe Theatre was built by Shakespeare,
actor Richard Burbage and others in 1599. Around the pit were
three layers of balconies. The highest balcony had a thatched
roof. In 1613 the thatch caught fire when a cannon was fired
during a performance of Shakespeare’s Henry VIII, and the
building burnt down. It was rebuilt in 1614, but thirty years
later, it was destroyed by the Puritans. In 1970 American actor
and director Sam Wanamaker raised funds to rebuild the
Globe. The latest Globe Theatre, based on the original,
opened in 1996.
Q Was theatre popular in the United States? Q What is Broadway?
A The first theatre in the United States
A New York’s Broadway has over 39
was the Dock Street Theatre in Charleston,
South Carolina that was built in 1736. The
building did not last very long. In 1937, a new
Dock Street Theatre was built exactly where
the original one had stood. At the beginning
of the twentieth century, the United States
produced some of the most memorable
modern theatre. Dubose Heyward became
famous with Porgy, a play using the Creole
language spoken by the African-Americans.
It was the world’s first international play and
the first to run for over 300 shows. Porgy
toured the United States and London.
Heyward and music composers George and
Ira Gershwin produced Porgy and Bess, which
has been called the best Broadway opera.
Vaudeville theatre of the United States
influenced early film directors in Hollywood,
and, through them, filmmaking all over the
world. American plays include some of the
classics of world theatre, such as The Streetcar
Named Desire and Cat on a Hot Tin Roof by
Tennessee Williams.
theatres. Broadway was the centre of
twentieth-century theatre. The two World
Wars inspired realistic plays that told the
stories of working class people. Eugene
O’Neill, Arthur Miller and Tennessee
Williams were among the most successful
playwrights of this period. The West End in
London is another hub of modern theatre.
It has nearly 40 theatres along streets like the
Strand, Drury Lane and Shaftesbury Avenue.
Try these too…
Ancient Greece
(128–129), Ancient
Rome (130–131), The
Renaissance (142–143),
Communication and
Satellites (192–193)
Plush theatre
Theatres such as this one
in Vienna, Austria, have
separate boxes. People
who hire these boxes
can watch a play
without anyone being
able to see them.
171
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Art and Culture
World of Sports
Sports have played a major role in every civilization. During
the hunter-gatherer days, throwing a spear, shooting an arrow,
running, wrestling, jumping and slinging a stone were part of the
hunt. When people learnt to grow crops and breed animals, they
did not have to hunt for food any more. But they have continued
to hunt for pleasure and to compete in games.
Quick Q’s:
Q How serious were the ancient
1. Have we learnt any
sports from early
cultures?
civilizations about sport?
Many popular sports
have been learnt from
earlier cultures. In
1778, Captain Cook
found the people of
Hawaii surfing. Native
Americans played
games like lacrosse.
The Mayans and Aztecs
played ballgames in a
court, which inspired
baskestball.
2. What are team
sports?
Sports played in a
group or team, where
two teams compete,
are called team sports.
Team sports like rugby,
football, handball,
basketball, throwball
and volleyball are
played with a ball. In
cricket, hockey and
baseball, a bat or stick
is used to hit the ball.
A The Greeks believed that
their gods liked humans to
be strong and fit. They were
especially fond of athletic
events. There were several
athletic competitions in
Greece. The most famous is
the Olympic Games and the
Isthmian Games at Corinth. Young
Greek men – mostly soldiers –
trained for sports. Besides running and
jumping, they trained to throw the discus
and the javelin. All these sports were part of
the Olympic Games. Girls were not allowed
to compete in the physical games. They
played dice, marbles and checkers. In
ancient Egypt, people played a game
like checkers. They also played
games with dice.
Playing ball
Baseball is very popular in
North America and Japan.
Q Who were the gladiators?
A By 300 , sports like chariot racing, horse
BC
racing and boxing were popular. The Romans
in particular loved to watch sports where
armed men and women, called gladiators,
fought one another to death. Sometimes, men
and women fought animals. Large stadiums
were built for these games. There were some
professional gladiators who took up this violent
sport out of choice or economic reasons, but
most of the people forced into the
Roman stadiums were slaves. The
Romans also played ludi pilae or ball
games and athletics. Under
several Islamic emperors,
polo became popular
in the Middle East.
It soon spread to
the Roman Empire
and to China.
Individual skill
sports like
gymnastics were
popular in ancient
China. In Egypt, where
the Nile was an important part of
life, swimming and fishing were
popular.
Q What were the games
played after that?
3. What is athletics?
All running events,
hurdles and race
walking are athletics.
All jumps and throws
like shot-put, discus
and javelin are also
athletic events.
Athletics also include
cross-country runs,
marathon and the
steeplechase, which
has a water barrier in
its 3,000-metre course.
172
A Board games like chess
Ancient sport
A gladiator takes up a
stance. In ancient Rome,
gladiators were either
mercenaries who fought
for money, or slaves who
were forced to fight,
either with other men or
with animals. It was cruel
but very popular.
and checkers became popular.
With the glass industry
growing, children began to
play marbles. Chess, which
was probably invented in India, spread to
Europe and the Middle East. Gladiator sports
came to an end but bull fights were fought in
amphitheatres. Several team sports like football
and hurling began in the Middle Ages. Horse
racing became popular in England.
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World of Sports
Five rings and an olive branch
Popular passion
Many sports, such as pole vault (top), swimming
(second from top), parachuting (centre), cricket
(second from bottom) and boxing (bottom) are
popular and are followed by thousands of people
across the globe. Professional sports are run like
multi-million dollar businesses.
Q Are sports still changing?
A In the nineteenth and twentieth
The Olympic Games are named after
Mount Olympus, where the ancient
Greeks believed that the gods lived.
The earliest recorded Olympic Games
were held in 776 BC in ancient Greece.
Since they were held every four years,
they made sport more organized and
very competitive. Winners were
honoured with an olive branch. In
1896, French educator Baron Pierre
de Coubertin revived the Olympics
to encourage international diplomatic
relations. Since then, the Olympics have
been held every four years, except in
1916, 1940 and 1944, during the two
World Wars. Even today, the Olympics
are the most important sports contest,
where the honour of the country
matters most. The Paralympic Games,
held at the same time and place as the
summer and winter Olympics, is for
those with physical disabilities and
cerebral palsy. These were first held
in Rome in 1960.
Indoor sport
A gymnast on the parallel
bars. Gymnastics is one of
the more popular of the
indoor games. It requires
a superb combination
of strength, fitness and
flexibility. While many
indoor games require
the same level of physical
fitness as outdoor games,
others are less physically
demanding.
centuries, cricket became popular in Britain
and in the former British colonies. In the
United States, baseball, a game similar to
cricket, got its set of rules in the 1840s.
Rugby, rather than football, became
popular there. With the Industrial
Revolution, better quality sports
equipment flooded the market.
With life becoming more urban
and routine, exciting sports like
hang-gliding, paragliding, bungee
jumping and canoeing have
become popular.
Q Are all sports played
outdoors?
A Even sports like tennis
and hockey can be played
indoors, in a covered stadium.
Games like chess, billiards and
bridge are nearly always played
inside a room. Gymnastics
and table tennis are indoor
games that require a lot of
physical activity.
Try these too…
Ancient Greece
(128–129), Ancient
Rome (130–131), Incas
and Aztecs (141),
Communication and
Satellites (192–193)
173
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Art and Culture
World of Movies
The clapper
Every shot in a film
starts with the top of
the clapper being brought
down to make a sound.
The board is used to record
the details of the shot.
The clapper has become
one of the symbols of
the film industry.
In the early nineteenth century, scientists noticed that if a series
of still pictures is made to move, it seems as if the image is
moving naturally. This moving picture is what developed into
movies, also known as motion pictures or films.
Q What was the daguerreotype?
A One of the first moving-image devices
Movie history
Radio City Music Hall in
New York had a famous
movie hall in the USA from
the 1930s to the 1970s.
Quick Q’s:
1. What is a
blockbuster film?
A blockbuster is a
very popular film
that generates huge
revenues. Jaws was the
first film to earn more
than $100 million. A
mechanical monster
shark was the hero.
2. What are science
fiction fantasy movies?
Science fiction or
sci-fi films are those
that deal with an
imagined scenario,
unreal scientific
discoveries or beings
from outer space.
George Lucas’s Star
Wars, made in 1977,
is a classic among sci-fi
fantasies. Steven
Spielberg, the director
of Jaws, made history
with sci-fi films like ET
and Jurassic Park,
where he combined
computer-generated
animation of dinosaurs
with shots of humans.
174
scientists used was a slotted disk with a series
of drawings, called the daguerreotype. When
the disk spun in front of a mirror, anyone
looking through the slots would see the
drawings move. In 1839, the
daguerreotype led to photography.
In the 1870s French inventor
Émile Reynaud developed the
first projector using a reflector
and a lens to enlarge the moving
images. By 1892, he was showing
his moving drawings at Théâtre
Optique in Paris. Each show
lasted for just 15 minutes.
These were virtually the first
film shows.
Q How did cinema develop?
A In the 1870s, Leland Stanford
laid a bet on whether all four feet of
a galloping horse were ever off the
ground at the same time. He hired
a British photographer Eadweard
Muybridge who photographed
a moving horse on 12 cameras.
The photographs showed the
horse with all four feet off
the ground. In 1889, George
Eastman introduced the
celluloid roll. Celluloid,
a material made from the
chemicals camphor and
nitrocellulose, was used
as a medium for film
photography.
In the 1890s, Thomas Alva Edison and his
assistant, William Dickson, invented the
kinetograph and the kinetoscope. The
kinetograph was a single camera that could
record a succession of images on to a moving
celluloid film. The kinetoscope was a large
coin-operated box that had a peephole
through which the ‘movie’ could be seen.
Q What are the Lumière brothers
famous for?
A In France, Auguste and Louis
Lumière ran a factory where they
manufactured photographic
equipment. In 1895 they developed a
hand-held camera, the cinematographe.
It could show large images on a screen
when attached to a projector. Their first
public screening was held in Paris in
December 1895. They made several films
during 1895 and 1896. They could even
bring a story into films. Waterer and
Watered, made in 1896, shows a boy
playing a prank to drench a gardener.
They also made films about real life, like
Workers Leaving the Lumière Factory,
1895 and Arrival of a Train at La
Ciotat, 1896. But cinema is not
the invention of any one person.
In Germany, Emil and Max
Skladanowsky also designed a
machine to project films in
November 1895. In Britain Birt
Acres and Robert W. Paul could
project films by January 1896.
The big prize
The Oscars are one of the main
awards given for films.
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World of Movies
Q
Which was the first real entertainment
movie to be shown?
A In 1901 American projectionist Edwin
S. Porter began making longer films that
told a story. His The Great Train Robbery,
made in 1903, was the first film shown for
entertainment. Nickelodeon theatres sprung
up in converted storefronts and charged
5 cents for a show. The first colour films
were hand-painted.
Q When did sound come in?
A Recorded sound was used in the late
1920s. Within just five years, sound was used
in almost every film. Once sound could be
recorded, musical films or musicals became
popular. Warner Brothers made films which
featured large groups of dancers. Their
earliest films were 42nd Street, Gold Diggers
of 1933, and Footlight Parade.
But colour was only used widely in the
1950s to lure television audiences. Sound
made animation films funnier. Walt Disney’s
first animated cartoon with sound was
Steamboat Willie of 1928. By 1937, after adding
colour to his films, he was making featurelength animation films in colour. The first
such film was Snow White and the Seven Dwarfs,
made in 1937. Animation films continued to
be popular and contributed to the success of
films like Jaws. In the 1990s, computer
graphics speeded up the animation process.
Hollywood Hill
Many of the world’s
biggest movies are made
in this part of Los Angeles.
Try these too…
Scientific Revolution
(150–151), The World
after World War II
(160–161), Light
(180–181), Electricity
(186–187),
Communication and
Satellites (192–193)
That’s huge!
Imax or Image Maximum makes movies huge. Over 700 million
people have watched an Imax movie. During Imax films, digital
surround sound technology is used to make the sound seem more
real and close. In an Imax theatre, the screen is high and wide
enough to include the whole visual field of the viewer. A standard
Imax screen is 22 metres wide and 16 metres high (72.6 x 52.8
feet). The world’s largest Imax screen is in Sydney, Australia.
Q What other types of films were
encouraged by sound?
A
With sound, directors could tell any
story. Horror films, featuring monsters and
murderers, became popular. During the
1930s, the films Dracula and Frankenstein were
made. Action films and dramas also became
popular with the introduction of sound.
Colour films started in the 1920s.
175
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Art and Culture
World Religions
Religion is a set of rules based on faith in a spiritual power.
Every civilization has its religion. Religion can also mean faith
in plants, animals, ancestors and spirits. Pantheism is the belief
that there is something spiritual in everything around us. The
word religion comes from the Latin noun religio, or rituals and
faith. Most religions practiced today were started long ago.
Ancient Egyptian gods
These gods were portrayed
as half-human half-beast.
Quick Q’s:
1. What is the meaning
of Zoroastrianism?
Zoroastrianism is a
religion founded in
Persia around the sixth
century BC by the
prophet Zarathushtra.
Arabs later banned the
religion. Zoroastrians
or Parsees fled to
India. Zoroastrianism
believes in one god,
Ahura Mazda. Their
holy book is the Avesta.
2. Who are the Amish?
The Amish are a
Christian sect known
for their shunning of
modern technology.
The Amish, who live
in the United States
and in Ontario
(Canada), avoid the
use of electricity and
cars as far as possible.
They do not join the
military, nor do they
take any money from
any government. They
place a high value on
humility, and are
strongly against pride.
176
However, they believed that these spirits
had superhuman powers and so they could
not be seen. Four of their main gods were
An, the god of heaven; Ki, the goddess of
earth; Enlil, the god of air; and Enki, the
god of water.
Q What is Judaism?
A Judaism, the religion of the Jewish
Q Which is the oldest religion in the world
people, has about 15 million followers
around the world. It began about 3,500
years ago in Palestine. Judaism is perhaps
the earliest religion to preach belief in one
god. The laws of God are known as the Ten
Commandments, which God revealed
to Moses on Mount Sinai. These laws are
written in the Old Testament of the Bible.
The Torah is the holy book of Judaism.
This religion influenced later religions that
began in the region, including Christianity,
Islam and the more recent Baha’i faith. The
Jewish temple is called a synagogue. Jewish
people believe they should pray three times a
day. Saturday or Shabbat is a day of rest and
prayer, to remember that God rested on this
day after creating the world in six days.
BC. It grew
from the four Vedas – religious texts written
by scholars. The Vedas contain hymns and
information about rituals. Hinduism believes
that the world was created by Bramha, and is
maintained by Vishnu. Any destruction in the
world is ascribed to Shiva. The two major
sects of Hinduism are Vaishnavism, or the
path followed by the followers of Vishnu,
and Shaivism, where Shiva is the main deity.
Apart from Bramha, Vishnu and
Shiva, the mother goddess,
in her many forms, is
worshipped
as Shakti,
or strength.
still practiced?
A Hinduism began before 1500
Q Did ancient Man believe in
religion?
A There are signs that every ancient
civilization believed in a higher power.
The ancient Egyptians worshiped many gods
like Anubis, Set, Osiris, Isis and Horus.
Egyptian Kings, called Pharaohs, were
believed to be God’s representatives on
Earth. The ancient Egyptians were the
first to prepare the dead for an after-life.
They buried kings and commoners with
many things they believed would be needed
in the after-life. The ancient Mesopotamians,
especially the Sumerians, had a strong belief
in several gods who took human form.
Hindu god
The elephant-headed god Ganesha is
one of the most popular of the Hindu deities. As in
other ancient religions, Hindu gods are often depicted
in various supernatural forms that are symbolic.
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World Religions
Q Who started Buddhism?
A Siddhartha Gautama was born in 563
Try these too…
Ancient Mesopotamia
(124), Ancient Egypt
(125), Ancient India
and China (126–127),
Native Americans
(133–135), Medieval
Europe (136–137)
BC.
Troubled by sickness, sorrow and suffering,
he left his palace to meditate or think about
life. When he found the answers to his
questions, he became known as The Buddha –
Enlightened One. Buddhism is practised in
Nepal, India, China, Myanmar, Thailand,
Japan, Korea and Sri Lanka, among others.
Q What is Christianity all about?
A Christianity is practised in every continent
where humans live. There are over 1.9 billion
Christians. They follow the teachings of Jesus
Christ, who lived about 2000 years ago. The
New Testament of the Bible, the holy book of
the Christians written after his crucifixion,
details the life and teachings of Jesus.
The headquarters of the Catholic Church
St Peter’s basilica in the Vatican – the seat of the Pope,
who is the head of the Catholic Church.
Shrine of the Báb
The tomb in Haifa, Israel,
of the founder of Baha’ism.
Started in the nineteenth
century, it is the world’s
youngest religion.
Old symbol
The menorah, the sevenbranched candlestick, is
one of the oldest symbols
of Judaism. It was used in
the Temple of Jerusalem.
On the calendar
Each religion sets aside certain days as important. For
Christians, Christmas, or the day Christ was born, is celebrated
on 25 December. Easter, the day Christ rose from the cross
where he was crucified, is commemorated on a Sunday in the
middle of April. For Muslims, Eid ul-Fitr marks the end of a
month of fasting during Ramadan. The date is decided by the
cycle of the Moon. Eid ul-Adha marks the end of haj, the
pilgrimage to Mecca. Jews celebrate their new year as Rosh
Hashanah, which they believe was the day the world was
created. Yom Kippur is the day of praying for forgiveness for
mistakes committed. Hindus celebrate several festivals. Diwali,
or the Festival of Lights, celebrates the victory of good over
evil. Dussehra celebrates the victory of Lord Rama in his battle
against the demon king Ravana. Buddhists celebrate Buddha
Purnima as the Buddha’s birthday.
Q When did Islam begin?
A The Prophet Muhammad founded Islam
in the seventh century AD in Arabia. Islam is
the second largest religion in the world. The
holy book of Muslims is the Quran. Muslims
believe that the Quran was revealed to Prophet
Muhammad by God through the Angel
Gabriel. Islam has one God. The word Islam
means ‘peace’ and ‘obedience to God’.
177
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Science and Technology
Matter
Everything around us is matter. Anything that occupies space
and has weight is matter. Matter is made up of atoms and
molecules. It takes three main forms: solid, liquid and gas.
All matter can change from one of these forms to another.
Quick Q’s:
1. What is plasma?
Plasmas are super-hot
atoms. A tube light
glows because the gas
inside the tube gets
charged up by the flow
of electricity and
creates plasma that
glows. The Northern
Lights are an example
of plasma occurring in
nature. Stars also have
plasma in them.
2. What is a
super atom?
Q What does matter look like?
A Matter is found in different forms and
shapes. It can be as huge as a mountain or as
tiny as gravel. It can be hard like diamond, or
as soft as silk. Even water is matter. A cube of
ice is the solid state of water. At the melting
point of water, or a little over 0 °C, the ice
turns in to water. If the water is boiled, it turns
in to steam or gas. When this steam meets a
cold surface, like a tile on the kitchen wall, it
cools and becomes liquid. Plasma, another
form of matter, can be made from a gas.
When some elements
are cooled to a
temperature just above
absolute zero, the
atoms begin to clump
together to become
one ‘super atom’.
Super atoms have
only been made in
laboratories for
fractions of a second.
178
Q What are solids?
A Anything that has a shape of its own and
occupies space or has volume is a solid. An
ice cube is a solid. When it melts in to water,
it turns in to a liquid that has volume but no
definite shape. If you pour the liquid
in to a spoon, it takes the shape
of the spoon. If you pour it back
in to the ice tray, it takes the
shape of the ice tray. If the
water is heated to a certain
temperature, it becomes vapour
or gas and has no definite shape
or volume. Gas expands to fill any
container you put it into.
Crystal of carbon atoms
A diamond is a transparent crystal of carbon atoms.
It is one of the many forms in which carbon is found.
3. Can I look at
an atom?
We cannot look at an
atom directly, even
through the most
powerful optical
microscopes, because
atoms are much
smaller than the
wavelengths of light
that optical
microscopes detect. A
human hair is as wide
as one million carbon
atoms. However, we
can detect the position
of an atom on the
surface of a solid with
an electron microscope,
so we know it is there.
Underground water
A geyser blows steam into
the cold air of Iceland.
The temperature
underground can be
so high that the water
turns into steam. This
steam then expands and
looks for ways out of
its chamber. When it
finds a pipe leading to
a hole on the Earth’s
surface, it gushes
out in the form of a
geyser. On contact with
the cold air outside, the
steam cools down and
turns back to water again.
All three forms
The ice cubes (top), the water in a cup (top right) and
the vapour in front of the kettle (above) are the three
forms in which water can be found – solid, liquid and
gas. All three forms are interchangeable, by adding or
taking heat energy away from the water. The chemical
properties of water remain the same in all states.
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Matter
Q What is matter made of?
A The tiniest part of all matter is an atom.
Several atoms form a molecule. Matter in
solid state, like the ice cube, gets its shape
because the atoms are packed close and tight.
In the liquid state, atoms are more loosely
packed. In the gas state, the atoms are even
more spread out and have lots of space
between them.
Q How does an ice cube become water?
A Adding more energy or taking away
energy from a substance changes its form.
When you add heat energy to an ice cube,
it turns to water. This is a physical change
since its shape and state change but the
chemical composition, or the atoms and
molecules, do not change.
Tiny orbit
Atoms are made up of three parts called
electrons, neutrons and protons. The
neutrons and protons form the nucleus,
or centre, of the atom and the electrons
move around the nucleus. An electron
has a negative electric charge, the proton
has a positive electric charge and the
neutron is neutral or has no charge. The
atomic theory was first developed by
John Dalton (below).
Different shapes
A liquid does not have a
specific shape but takes
the shape of the
container in which it is
poured. This is because
the atoms that make up
the liquid are freer than
they are in solid form, so
they move about more
and occupy all the space.
Q What are chemical changes?
A Sometimes, adding or taking away
energy changes the substance so much that
no amount of heating or cooling can turn
it back to what it was. This is called a
chemical change. When you heat or toast
bread, it turns brown and finally gets burnt
or black. No amount of cooling can turn
this brown bread white again because the
bread has been through a chemical change.
Q What is a compound?
A All matter is made up of some basic
substances called elements. Elements are
natural substances. They cannot be made
artificially. Oxygen is an element. If two or
more elements are combined in such a way
that they can be separated again, it is called a
mixture. When you combine two or more
elements to make something new that cannot
be changed, you get a compound. If you heat
iron and sulphur, it will form iron sulphide,
which is a compound.
A chemical change
When you toast a slice
of bread, it is a chemical
change. The heat leads to
chemical reactions in the
bread, so that it hardens
and changes colour.
Try these too…
Stars (8–9), The Sun
(10–11), The Planets
(12–13), The Moon
(20–21), Comets and
Asteroids (22–23), The
Renaissance (142–143),
The Industrial Revolution
(148–149), Scientific
Revolution (150–151)
Plasma
This is matter in its plasma
state, the fourth state of
matter. When gases
become very hot like in
these neon tubes, they
turn in to plasma and
start glowing. In this
state, electrons and
protons move about
freely, so that the matter
is said to be ionized.
Neon lighting is used
widely in cities.
179
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Science and Technology
Light
Light is a very important part of our lives. Without light we
would not be able to see the beautiful world around us, and it
wouldn’t even exist. Light is essential for life to thrive on this
planet. Animals and humans depend on plants for their food.
Plants make their own food, but they cannot do so without light.
Quick Q’s:
Q
1. What is a light year?
How long does it take for sunlight
to travel to the Earth?
The distance that light
travels in a year is
called a light year.
A Light from the Sun takes about eight
2. What colour is light?
Light usually appears
white, but is made up
of various colours of
the rainbow: violet,
indigo, blue, green,
yellow, orange and
red (VIBGYOR).
3. Why does the Sun
look like a red disc
during sunrise
and sunset?
During sunrise and
sunset, the sunlight
has to travel a much
longer distance than
during the rest of the
day. The scattered blue
light is not able to cover
this extra distance and
therefore does not
reach our eyes. The
red light reaches us, as
the wavelength of red
is longer. This helps
red light travel further.
This is why the Sun
appears like a red disc.
4. What do the words
‘opaque’ and
‘transparent’ mean?
Solids are said to be
opaque, as they do
not allow light to pass
through them, while
water and glass are
transparent as light is
able to pass through.
180
minutes to reach us on the Earth. This is
because sunlight travels at an incredible
speed of about 300,000 kilometres per second
(186,000 miles per second). Nothing in this
universe travels faster than that!
Source of light
Light is actually a form of energy that is produced by
both natural and artificial sources. A light source is any
object that gives off light. The Sun is the main natural
source of light. Artificial sources of light include candles
and electric bulbs.
Q Does light always travel in a straight line?
A Light travels in a straight line unless an
object is placed in its path. If the object is
solid the light bends around the edges of
the object, creating a shadow. If you place
a mirror in its path, the light hits the surface
and gets reflected. If you use a transparent
object, the light goes through it, but its
direction is altered slightly. This phenomenon
is called refraction.
Q Why are we not able to see objects on
the other side of a wall?
A We are able to see an object when light
bounces off that object and reaches our eyes.
However, solid objects like a wall block the
light from passing through to the other side.
Instead, the light hits the wall and bounces
back. Therefore, we are able to see the wall
but not the objects on the other side.
A matter of colour
The colour of an object is determined by the colour
of the light it scatters – an object appears green because
it scatters green and absorbs the rest of the colours. A
black object is black because it does not scatter any light.
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Light
Q Glass is also a solid object, yet how are
Mirror, mirror!
we able to see through it?
Light usually bounces straight back when it hits a solid object.
We can see the object, but it doesn’t reflect anything. However,
some objects also absorb a part of the light that falls on them and
reflect it. Others reflect all of the light that falls on them. These
objects create reflections. Reflections are seen best on mirrors
as they have smooth, flat surfaces that reflect light better. When
you stand in front of a mirror, the reflected light from it falls
on you and therefore you are able to see an image of yourself on
the mirror.
A
The molecules of solid matter are usually
packed tightly together, and therefore do not
allow light to pass through them. In liquids
and gases, the molecules move about freely
and there is a lot of space between them.
That is why light is able to pass through these
materials easily. Glass is made by first melting
sand, and then cooling it. The substance made
has the rigidity of a solid, but still has the free
moving molecules of a liquid. So the space
between the molecules of glass allows light to
pass through, although glass itself is a solid.
Q How are rainbows formed?
A A rainbow is created by the refraction of
sunlight by water droplets in the atmosphere.
When sunlight passes through a drop of water,
it is bent in such a way that the various colours
that make up white light are split. Each colour
is bent at different angles. Red bends the
least, while violet is bent the most. It is this
phenomenon that we see as a rainbow.
A rainbow of colours
The rainbow is always formed on that portion of the sky
that is directly opposite to the Sun. A rainbow is not
composed of just seven colours. In fact, it also contains
colours like infrared that cannot be seen.
Q Why is the sky blue?
A The Earth’s atmosphere contains tiny
molecules of gas and dust particles. Sunlight
entering the atmosphere hits these molecules
and dust particles. Colours with longer
wavelengths, like red and yellow, can pass
through the atmosphere without being
scattered by these molecules of gas and dust
particles. But the colour blue, with its shorter
wavelength, is scattered by the gas molecules
and the dust in the upper atmosphere. This is
why the sky appears blue.
Try these too…
Galaxies (6–7), Stars
(8–9), The Sun (10–11),
The Industrial
Revolution (148–149),
Scientific Revolution
(150–151)
Blue water
Water is actually colourless. However, large amounts of
water act like the sky and scatter blue light. This is why
seas, lakes and rivers usually appear blue.
181
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Science and Technology
Sound
Sound is a form of energy that is transferred by pressure waves
in air or through other materials. These waves can be picked up
by the ear, which is how we hear sounds. But there are many
sounds around us that our ears do not pick up, and so we do
not hear them.
Quick Q’s:
1. What is the range of
sound that the human
ear can catch?
A young human being
can hear almost all
sounds from 15 Hz to
20,000 Hz. With age,
you hear less, and find
it difficult to catch
higher frequencies. A
human voice carries
sound at about 60 Hz,
but a shout can reach
13,000 Hz. Elephants,
dogs and other animals
can hear ultrasonic
sound that we cannot.
2. How does ultrasonic
sound help doctors?
Ultrasonic sound waves
help doctors locate
and diagnose medical
problems, because
different tissues reflect
sound waves in
different ways. Using
this method, doctors
can also monitor the
development of a
foetus during pregnancy.
3. How do I speak?
Human beings have
vocal chords inside the
larynx which produce
sound. When air passes
through a gap between
the chords, these
chords vibrate and
produce a sound.
All animals that can
produce a sound have
vocal chords, except
birds which produce
sound through a bony
ring, called a syrinx.
182
Q How does sound move?
A Sound needs a medium like air, water or
solids to travel through. When something
moves through the air, it disturbs the
molecules of gas in the air around it. The air
vibrates or moves back and forth. This
vibration is heard as sound. The greater the
vibration, the louder the sound. Since sound
travels in waves, it gets weaker the further it
travels. That is why your voice cannot be
heard beyond a certain distance. If you put in
more energy and shout, the sound waves will
be stronger and travel further so that your
voice can be heard further. Sound cannot
travel through a vacuum, because a vacuum
is completely empty, and has no medium
with which to carry the sound wave.
Q Can you measure sound?
A Sound is measured in several ways:
frequency, wavelength and amplitude. Sound
waves vibrate at different rates. These are
called frequencies, measured in cycles per
second or Hertz (Hz). 1 Hertz = 1 vibration
per second. A wavelength measures the
length of one cycle. Longer wavelengths
have a lower pitch. The lowest tones that a
human can catch are about 16 vibrations
per second, or 16 Hz. Amplitude measures
how loud the sound is. A sound wave of high
amplitude will produce a
louder sound. It is measured
in decibels (Db).
Music to the ears
Music generally conforms
to eight notes or an octave.
All other sound is noise.
Although most of us agree
on what music is, there can
be disagreements. For
example, people beating on
pots and pans can create
unusual music.
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Sound
Q Does sound travel as fast as light?
A Sound travels far slower than light. Light
travels at 299,337 kilometres per second,
(186,000 miles per second) and sound travels
at about 8 kilometres per second (5 miles per
second). This is why we see lightning before
we hear thunder. If you hear a clap of
thunder ten seconds after you see a flash
of lightning, then the lightning struck
3.6 kilometres (two miles) away.
How the ear hears
When sound energy reaches the outer ear, the eardrum that
separates the outer and middle ears transmits this sound inside,
where it is converted into nerve signals and sent to the brain.
The brain tells us what we hear. We hear our own voice much the
way we hear other sounds, and also by bone conduction. The
vibration of the voice makes the bones in our skull vibrate.
These vibrations are picked up by the inner ear. That is how some
people with hearing problems can be helped with a hearing aid
that transfers sound vibrations to the skull bones.
Q What is an echo?
A Sound waves can be reflected off any
reasonably flat surface like a cliff, high wall or
mountain. When this surface is neither too
near nor too far, a sound made by you hits
the surface and comes back to you as an
echo. The further the surface is from you, the
weaker the echo and the longer it will take
for the echo to return. The waves keep
bouncing back and forth, getting weaker as
they travel, until they lose energy and die out.
Sonic boom
When an aircraft flies faster than the speed of sound, it
is hitting the sound waves in front before those waves
have moved away. So successive sound waves are
getting mixed up. This creates the sonic boom.
Q How does an aircraft break the
Try these too…
sound barrier?
The Industrial Revolution
(148–149), Scientific
Revolution (150–151),
The World after World
War II (160–161), Music
(168–169)
A Supersonic aircraft travel at a speed
greater than that of the speed of sound,
which is about 1,220 kilometres per hour
(760 miles per hour). The first supersonic
flight was in 1947 by a Bell X-1 rocket plane
flown by Chuck Yeager. These aircraft
measure speed in Mach. Mach 1 is the speed
of sound. At less than Mach 1, the aircraft
is flying at a speed lower than the speed
of sound or is subsonic. At Mach 1, it is
travelling at the speed of sound or is
transonic. Speed between Mach 1 to 5 is
supersonic. Above Mach 5 is hypersonic.
At supersonic speed and above, an aircraft
creates such a strong shock wave that it is
heard on ground as a sonic boom. This
can be so loud that most supersonic aircraft
fly above Mach 1 only above the ocean,
where few people outside will be troubled
by the sonic boom.
Sharp ears
Dogs can pick up a lower
frequency than humans
can. Dog whistles are
made on this principle.
183
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Science and Technology
Heat
Heat is a form of energy that is created by atoms moving. Even
things that are cold have some heat energy because their atoms
move, albeit slowly. When we feel cold, we jump up and down for
warmth to get our atoms moving! Heat energy is also known as
thermal energy. Many types of energy like light, chemical, sound
and nuclear can be converted into heat energy by increasing the
speed of the atoms in the object producing the energy.
Quick Q’s:
1. What is
thermodynamics?
Thermodynamics is the
study of heat and how
it can help us.
2. Why do things
expand when heated?
When you heat solids,
liquids or gases, they
expand because the
molecules start moving
faster. To move fast,
they need more space,
so they expand.
3. What is
boiling point?
The temperature at
which a substance
changes from liquid to
gas is called its boiling
point. The melting
point of a substance is
the temperature
at which it changes
from solid to liquid.
4. What are good
conductors of heat?
Metals are the best
conductors of heat.
That is why cooking
pans are made of metal
to carry the heat from
the stove to the pan.
Wood and plastic are
poor conductors. That
is why the handles of
cooking utensils are
often made of these
materials, so we don’t
burn our hands!
184
Q Where do we find heat?
A The largest source of heat in nature is
the Sun. The Sun is a burning ball of fire
whose average surface temperature is 6,000 ºC
(10,800 ºF), about 400 times the average
surface temperature on Earth. In the kitchen,
we need heat to convert raw food into
something that is digested easily. We use gas
or an electric oven to heat our food. Before
stoves, heaters and ovens running on gas or
electricity were developed, the heat for
cooking was provided by burning wood or
coal. Vehicles like cars move with the heat
that comes from burning fossil fuels like
petrol and diesel. Machines like a knife
sharpener or an electrical saw generate heat.
Our bodies get heat energy from the food we
eat. But ultimately, the source of all this heat
is the Sun. Even the fires that burn under the
Earth’s crust produce heat that originally
came from the Sun.
From heat to light
The heat energy produced
by the burning of the
matchstick also produces
visible light. The lighted
match is used to light the
wick of the candle.
As the wick catches fire,
it produces heat. Some
of this heat energy is
converted into light
energy that we see.
Another portion of the
heat energy melts the
wax to provide fuel, so
that the entire process
can continue.
Q How is heat measured?
A Heat is measured with a thermometer.
A thermometer is a glass tube that ends in
a bulb containing mercury. Numbers are
written on the tube. The mercury in the bulb
heats up when it touches something hot, like
the inside of your mouth. As a result, the
mercury expands and rises up the tube. If
we do not have a fever and are resting, the
mercury will stop at 37.0 ºC (98.6 ºF). When
we are unwell and have a fever, the mercury
rises further, and the doctor knows how high
the fever is.
Q What is heat energy used for?
A We use heat energy every day. Electrical
energy is converted into heat energy in
appliances like electrical stoves, toasters,
hair dryers and light bulbs. When you boil
water, heat energy from the stove makes the
molecules in the pan move faster. This heats
up the pan. This heat from the pan, in turn,
makes water molecules inside it move faster
and heat up. That is why the water heats up
only after the pan is hot. Heat energy does a
lot of work for us. The earliest trains ran on
thermal power from burning coal.
Using heat
One of the most common uses of heat energy is for
cooking food. The heat leads to chemical changes, which
turns raw food into cooked food that we can digest.
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Heat
Q How is heat transferred from one thing
The largest source of heat energy
to another?
Heat energy from the Sun is known as solar energy. Rays from the
Sun heat the surface of the Earth, the oceans and the air above.
Taking a hint from the Sun’s natural heating capacity, scientists
have made solar cells from which we can get electricity. When
sunlight touches a solar cell, it causes a chemical reaction and
electricity is generated. Solar panels can heat water and cook food
and solar cells can even run a car. Fossils fuels like petroleum
have to be mined from the Earth, and one day we will use them
all up. But solar power will not run out for millions of years.
A
Heat is transferred by conduction,
convection and radiation. Conduction means
the transfer of energy from one molecule to
the next molecule. Whenever two substances
come close to each other, heat flows from the
warmer to the cooler substance through
conduction. Convection is when a source of
heat warms up a liquid or gas due to
movements of currents inside the liquid or
gas. This is how water boils. Radiation is the
transfer of heat in straight lines like the rays
of the Sun. Direct radiation from the Sun can
be dangerous because it contains ultraviolet
rays that damage our skin.
Q How can I light a fire?
A When two things rub against each other,
it is called friction. This generates a lot of heat,
sometimes enough heat to light a fire without
matches. People struck pieces of flint to light
a fire before matches were developed. Even
today, when you light a match, it is friction that
causes the matchstick to catch fire.
Transfer of heat in a microwave oven
Microwave radiation passes through the food inside this
oven. Some molecules in the food absorb energy from
the microwave beam and start moving around. This
movement produces heat that cooks the food.
Conduction
Convection
Radiation
Ways of heat transfer
Heat travels through solids by conduction. Most metals
are good conductors of heat, while wood is a poor
conductor. That is why frying pans are made of metal,
but often have a wooden handle. As the diagram shows,
convection currents first move upwards. Heat transfer
by radiation takes place in all directions.
Try these too…
The Sun (10–11), The
Industrial Revolution
(148–149), Scientific
Revolution (150–151)
185
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Science and Technology
Electricity
Father of the
battery
Alessandro Volta was
an eighteenth-century
scientist who
developed the voltaic
pile. This was later
developed into a
battery. The measure
of strength of
current, voltage, is
named after him.
Electricity is a secondary source of energy. We have to generate
electricity from primary sources of energy like moving water,
nuclear power, coal or natural gas. It can be converted in to other
forms of energy like light or heat. Electricity is used for lighting
and heating or cooling our homes. It runs machines to wash
clothes and dishes and to cook. It brings us information through
computers and television.
Q Who discovered electricity?
A Ancient Greeks knew that electricity
Electric animal
One of the large electric
eels of South America can
deliver a shock powerful
enough to kill a human.
Quick Q’s:
1. If electricity lights a
bulb, does it also light
my torch?
A bulb is lit with
electricity from a
power generator.
Another source of
electricity is the
battery. It has
chemicals that react
and produce a small
amount of electricity,
enough for a torch.
2. How do power
stations generate so
much electricity?
Power stations convert
the kinetic energy
of moving water
(hydroelectricity), heat
produced by burning
coal (thermal
electricity) or by a
nuclear reaction
(nuclear power), the
kinetic energy of wind
that turns a windmill,
tide movements (tidal
power) or heat from
inside the Earth
(geothermal power) to
generate electricity.
186
could be produced by rubbing two pieces of
felt together. But the first use of the word
electricity was by Sir Thomas Browne in his
1646 book Pseudodoxia Epidemica (Vulgar
Errors). In 1752, Benjamin Franklin proved
that lightning was created by electric charges.
He tied an iron key to a kite string during a
storm and showed that the lightning hit the
key. For this reason, Franklin is said to have
discovered electricity. Today, we know that
lightning is the most commonly seen form of
natural electricity. It is caused by clouds
carrying a negative charge that bump in to
positively charged objects on Earth.
Q What is electricity?
A Everything is made of atoms. At the
centre of an atom is the nucleus made of
protons and neutrons. An atom also has tiny
electrons which spin around the nucleus.
Electrons have a negative electrical charge,
and protons have a positive charge. The
electrons don’t stay in one place. They move
around to different atoms, so some atoms
have more protons, some have more
electrons. An atom with more protons is
positively charged. One with more electrons
is negatively charged. When the electrons
pass from one atom to the next, it creates
an electric current.
Q Can electricity make my hair stand
on end ?
A Static electricity is created when you rub
against a charged surface. The extra electrons
move from your body or the other way
around, and a tiny spark of electricity is
created. Static makes dry hair stand on end
after you run a plastic comb through it.
Natural electricity
The lightning that transfers electrons from negatively
charged clouds to positively charged substances on the
surface of the Earth is the biggest source of natural
electricity we know of. Lightning can be dangerous to
someone caught outdoors. Anyone caught outdoors
during a thunderstorm should keep as low as possible.
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Electricity
Q How is electricity measured?
A Voltage is the measure of the strength of
an electric current. The unit for measuring
voltage is the volt. A voltameter tells us how
many electrons are sent from one end of the
circuit and how many are received at the
other end. The distance electricity travels
affects its quality, especially if it is prevented
from flowing freely because of resistance.
Resistance is a material’s opposition to the
flow of electric current through it. Resistance
is measured in ohms. Scientists are always
looking for materials like copper that are
good conductors of electricity and have a
low resistance. Silver is the best conductor,
but it cannot be used in wires in our homes
because it is too costly. Most metals are
good conductors.
Electric brain
Without electricity, we wouldn’t be able
to feel anything! The human body has a
continuous flow of electric current
through our nerve cells. That is how the
nerve cells convey messages to the brain,
and we know that our back is hurting, or
that someone is standing on our foot. In
its turn, the brain uses these tiny electric
currents to send commands to the rest of
our body. Your hand turns the page when
the brain commands it to do so.
Q How does a light bulb work?
A The electric bulb is made of transparent
or translucent glass and has a delicate wire
called a filament. It has to be thin so that its
atoms collide more often when an electric
current is passed through it. That is how it
glows. Thomas Alva Edison made the first
practical, workable bulb for home use.
Compact fluorescent lamps that use less
energy than other bulbs have become
increasingly popular since the 1980s.
Inside a bulb
Scientists
experimented with
Inert gas
the conversion of
Support wires
electrical energy
to light
throughout the
nineteeenth
century. In 1801,
Humphry Davy
made platinum strips
glow by passing an
electric current through
them. Seven different
types of light bulbs were
patented in that century
before the first could be
used at home.
Tungsten
filament
Changing skyline
The night skyline of almost
every city in the world
has changed dramatically
in the last 100 years or
so, after electricity came
into widespread use
for lighting.
A hydroelectric
power station
Water is held in a dam.
Then a bit of the water
is allowed to run through
a channel, turning the
blades of a turbine
connected to a generator.
Try these too…
The Industrial
Revolution (148–149),
Scientific Revolution
(150–151), Magnets
(188–189)
Bulb
Glass mount
Screw thread
contact
Insulation
Electrical foot
contact
187
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Science and Technology
Magnets
Any object that attracts metals like iron, cobalt, nickel or steel
to itself is a magnet. A magnet can push away or repel other
magnets. Some magnets, like iron, are very strong, while other
magnets are much weaker.
Quick Q’s:
1. Why do things stick
only to the poles of
the magnet?
Magnets are strongest
at their poles so objects
stick to one of the
poles most easily.
2. How can you destroy
a magnet?
Though magnets can
be natural or manmade, dropping,
heating or hammering
them can destroy
them, especially if they
are small and weak.
3. Can you store
a magnet?
Magnets get weaker
with time. The best
way to store them is
to keep them in pairs
with the unlike poles
next to each other
and placing keepers
or pieces of soft iron
across the ends. The
keepers become
temporary magnets
themselves and keep
the magnetic force
stronger.
4. What is an
electromagnet?
Winding an electric
wire around a piece
of iron can make
electromagnets. When
electric current runs
through the wire, a
magnetic field is
created. The iron piece
picks this up and
becomes a magnet.
188
Q How did people find out about magnets?
A The magnet was discovered in China as
early as 200 BC. Around the same time, the
Chinese found that from a magnet, one
could find out directions like north and
south. Sailors in most civilizations began
to use a certain type of magnet called a
lodestone to navigate. It is the most magnetic
substance on Earth. In the sixteenth century,
Sir William Gilbert discovered that a piece of
iron could acquire the properties of a
lodestone if you rubbed it with a lodestone.
That allowed scientists to create many more
magnets. People were no longer dependent
on the few natural lodestones they could find.
Today, magnets are made of a blend of
different materials that contain some or all
of iron, nickel, copper, cobalt and aluminium.
Q What are poles of a magnet?
A Just as the Earth has two poles – the
North and the South poles, a magnet also has
two poles. It is easiest to find the two poles
of a bar magnet where the poles are at either
end are equally strong. The north seeking
pole of the bar magnet points towards the
Earth’s North Pole. The other end points
towards the South Pole. But if you use the
magnet for navigation, you must remember
that the magnetic poles of the Earth are not
in exactly the same positions as the
geographic poles of the Earth. Also,
if you hold two bar magnets next to each
other the poles will not point in the same
direction because the magnets interfere with
each other. The like poles repel each other
while the unlike poles attract each other.
Magnetic scientist
Michael Faraday (1791-1867), an English scientist, led
the study of electromagnetism. He showed that
magnetism could affect rays of light.
Q What is a magnetic field?
A The area around a permanent magnet
has a force that can affect other magnets or
magnetic materials that come near it. This
area is called a magnetic field. Even the Earth
has a magnetic field. It is like a huge bar
magnet. Even if you cut a huge bar magnet
into tiny pieces, each piece is still a magnet
with its own small magnetic field.
Fridge magnets
Most of us are familiar with the pretty and useful
magnets we stick on the refrigerator.
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Magnets
Paper clip power
Any magnetic material in touch with a
magnet starts behaving like a magnet
itself. If you hang a paper clip from a
magnet, it becomes a temporary magnet.
You can prove it by hanging a second
paper clip from the first and then
another and another. However, if you
remove the first clip from the magnet,
all the clips below fall apart since they
lose their temporary magnetism.
Horseshoe magnet
You can play a variation of the paper clip game
with a horseshoe magnet, which has its two poles
adjacent to one another. Since the opposite poles
are much closer, a horseshoe magnet produces a
relatively strong magnetic field – you can stick
many more clips to the magnet, starting with one
that is stuck to both poles.
Q Are mariners the only people who need
magnets for their work?
A Magnets are used almost
everywhere in modern life. Most
electrical appliances, from power
stations to the little hair dryer at home,
use a magnet to convert electrical
energy into mechanical energy.
Cassettes are coated with magnetic
material that allows sound to be
recorded on its surface. Credit cards
have magnetic strips that contain
encrypted information and enable us
to use them. Motors found in
dishwashers, fans, washing machines,
refrigerators, CD, DVD and audio
players use magnets. Magnets are also
used to hold false teeth in place. And
they help you remember too – by
holding your notes to the refrigerator!
This way to the North
Try these too…
The Poles – The
Arctic and Antarctica
(122–123), The
Industrial Revolution
(148–149), Scientific
Revolution (150–151),
Electricity (186–187)
The compass
Even a small pocket
compass can show you
the exact direction in
which you are travelling.
Remember that it is not
the point marked North
but the needle that is
always pointing to the
magnetic North Pole. In
some compasses you can
rotate the dial and align it
with the needle to help
you find which way is
true north. The Earth’s
magnetic poles shift
periodically. The needle
points to the current pole.
189
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Science and Technology
Forces and Motion
Force can change the state of an object. If an object is
stationary, force can get it to move. Once it is moving, force can
make the object accelerate or pick up speed. It can also stop a
moving object. A stationary object cannot move without force,
nor can a moving object stop without force.
Quick Q’s:
1. What is net force?
When more than one
force acts on an object,
the total of all forces
acting on that object is
called the net force.
When more than one
force acts on an object
in the same direction,
the object moves faster.
If the forces act in
opposing directions,
they cancel each other
out to a certain extent.
2. What is lateral
deflection?
It is a force that makes
a bullet spin to one
side, or a football curl
through the air. During
the Soccer World Cup
in France in 1998,
Brazilian Roberto
Carlos scored a free
kick with a perfect
lateral deflection.
He kicked the ball
to the far right of the
defenders and made it
suddenly curve round
and zoom into the goal.
Q Where is force used?
A Force is used in all our activities from
brushing our teeth to walking, lifting and
writing. Every one of our actions requires
some force. You need energy to create force.
Machines use force to move something or
to build something.
Q What is inertia?
A An object tends to carry on doing the
same thing, whether it is at rest or moving,
unless a force acts on it to change that. This
is called inertia. Your pencil box lies on the
table until you push it. This state of rest is
called inertia of rest. Then, with the force of
your finger, it moves on until it meets another
force that stops it. This movement is called
inertia of motion. If the force you push the
object with is too much, it will go beyond the
point where you wanted it to go.
Q What is gravitational force?
A Gravity is the force that Sir Isaac Newton
discovered, as he watched an apple fall off a
tree on to the ground. It is a force that draws
everything in the Earth’s atmosphere and
beyond towards the centre of the Earth and it
keeps us on the ground. Gravity does not just
act on the Earth; it is the force of attraction
between all bodies (things) in the universe.
The science of a kick
The force of the kick makes the ball
move. The force used by someone
else’s foot makes it stop.
190
The discoverer of gravity
Sir Isaac Newton (1643–1727) is supposed to have
discovered gravity after seeing an apple fall from a tree.
As bodies get closer together, the force of
gravity gets stronger, and as they move apart,
gravity gets weaker. Bigger, heavier bodies
are affected more by gravitational force.
They also exert a greater force of gravity
themselves. Gravity holds the solar system
together and keeps the Earth close enough
to the Sun for us to get the warmth we need.
Q How do I stay on a merry-go-round
without flying off?
A You stay on a merry-go-round because
of centripetal force. When you feel you are
going to fly off into the air, it is because
your body wants to keep moving in the
same direction all the time. This feeling
is the inertia of motion. But the centripetal
force keeps attracting you to the centre of
the merry-go-round, making sure you stay
on board! Objects set in motion normally
move in a straight line because of inertia of
motion, unless some other force acts upon
them and changes their path. When a ball
tied to a piece of string is swung round, the
centripetal force acts upon the ball, attracting
it to the centre of the circle. The centripetal
force from the string pulls the ball to keep it
on its circular path.
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Forces and Motion
Q What is the difference between speed
Torque
and velocity?
The force that causes rotation is called
torque. Torque can be measured in
opening or closing a door, and it is
applied when you turn a racquet from
side to side. An archer applies torque to
move the bow to one side when aiming
an arrow. Ideally, the archer should hold
the bow loose enough so that when the
arrow is released, it shoots straight
ahead. If the archer applies unnecessary
pressure, the bow will twist upon release,
the arrow will not fly straight, and the
shot will miss the bull’s eye.
A
Speed is the distance travelled by an
object in a particular time. Velocity is speed
in a particular direction. Suppose you sat
in a train that was moving eastwards at
60 kilometres per hour (37 miles per hour).
You would say that the speed of the train was
60 kilometres per hour (37 miles per hour),
while its velocity was 60 kilometres per hour
(37 miles per hour) east.
Q What is friction?
A Friction is a force that opposes the
movement of an object by acting on it in the
opposite direction. The force of friction
comes into effect when two surfaces are in
contact, and force is applied to make one or
both of the surfaces move. Suppose you roll a
ball on the floor. The ball will come to a halt
after travelling a certain distance, even if it
has hit nothing or no one has stopped it. The
ball stops because the friction exerted
by the floor acts against the motion
of the ball. The soles of your
new shoes probably have
cuts in them to make an
uneven surface.
When you run, the uneven surfaces of the
shoes and the road rub against each other.
This friction makes sure you do not slip while
you are running. Lack of friction also causes
us to slip on a wet floor since the water makes
the floor smooth, which means friction is
reduced. Friction produces heat. That is why
when you rub a matchstick against a
matchbox, sparks fly.
Try these too…
Galaxies (6–7), Stars
(8–9), The Sun (10–11),
The Moon (20–21),
Hurricanes and
Tornadoes (40–41), The
Industrial Revolution
(148–149), Scientific
Revolution (150–151)
Sitting pretty
We stay on the merry-go-around
instead of flying off in one
direction because of the centripetal
force that holds us to its centre.
The force that wants to make
us fly off is called the
centrifugal force.
191
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Science and Technology
Communication and Satellites
A satellite is an object that orbits other objects in space. This
includes natural satellites like the Moon and artificial satellites
made by people. The term satellite came to be used after
Galileo Galilei discovered the four main moons of Jupiter.
Quick Q’s:
1. When was the first
artificial satellite
launched?
Sputnik 1 was launched
by the then USSR on
4 October 1957. It
reached a height of
about 250 kilometres
(150 miles) and
collected information
about the furthest
reaches of the Earth’s
atmosphere. Three
months later, it burned
up completely as it
came back to Earth.
2. Who owns the
satellites?
The first satellites were
owned by countries.
Today, with satellites
becoming cheaper and
doing more work,
companies also own
satellites. The area on
the surface of the
Earth covered by the
satellite’s signal is
called its footprint.
3. What is a
constellation?
Groups of satellites
doing the same kind
of work are called a
constellation. The
Global Positioning
System is one such
constellation made up
of twenty-four satellites.
GPS works in any
weather condition,
anywhere in the world,
24 hours a day. A GPS
instrument can tell you
exactly where on Earth
you are.
192
Q What does an artificial satellite do?
A Artificial satellites have been put to a
wide range of uses. Some satellites send and
receive television signals so that we can watch
many television channels. If there are enough
satellites in space, one television programme
can be seen all over the world at the same
time. Weather satellites help scientists called
meteorologists predict what the weather will
be like. These satellites can save hundreds of
lives by warning fishermen not to sail before a
storm, and predicting when a hurricane will
strike. Some satellites take photographs of the
Earth’s surface so that scientists can study
changes in the world. This is how scientists
know that glaciers that are millions of years
old are melting because of global warming.
Some others are communication satellites
that deal with telephone, fax, internet and
computer communications.
Watching a live game
The images captured by the television camera are sent
instantly around the world via satellites.
Satellite television
Satellites bring television signals from all over the world
instantly into our homes.
Q What is an orbit?
A Artificial satellites are given a definite
path around the Earth. The Earth’s gravity
holds the satellite in a path called an orbit.
There are several kinds of orbits. One is Leo
or Low Earth Orbit. A Leo satellite circles
160–480 kilometres (100–300 miles) above
the Earth’s surface. It has to travel very fast
to avoid being sucked back to the Earth by
gravity. Leos travel at about 28,164 kilometres
per hour (17,500 miles per hour) and can
circle the Earth in less than two hours.
Medium Earth Orbit or Meo satellites are
placed 9,656–19,312 kilometres (6,000–12,000
miles) above the Earth. They are often used
for communications of all kinds. Geos
or Geostationary Earth Orbit satellites circle
the Earth in 24 hours, which is the time the
Earth takes to rotate once on its axis. So they
seem to be fixed above one spot on the Earth.
Geo satellites orbit 35,859 kilometres (22,282
miles) above the Earth. They carry television
signals across the world, telephone calls
between countries and internet messages.
They also help predict the weather.
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Communication and Satellites
Q How does the satellite get into space?
A A satellite is launched into space on a
launch vehicle which is driven by a rocket
engine. There are special launch stations
for satellites like Cape Canaveral in the USA,
Baikonur in Kazakhstan, Kourou in French
Guiana and Xichang in China. To start with,
launch stations were run by countries or
national organizations. Nowadays there are
large private companies that also run some
launch stations and provide the service of
launching a satellite on a commercial basis.
These launch stations must be far from
human habitation so that the falling launch
vehicle lands in water or on desolate land.
Some satellites are launched from a portable
platform on the Pacific Ocean. The launch
vehicle’s rockets carry the satellite into a
temporary orbit. The rockets and the launch
vehicle drop off. Then the satellite is ready
to take off on its own motor. When it reaches
its permanent orbit, the antennae and solar
panels open up and the satellite starts sending
and receiving signals.
Q What is a Comsat?
A Communication satellites or Comsats
help in long distance communication by
receiving and redirecting radio, television
and telephone signals. Today, satellites
provide a cheaper and better global
communication network compared to many
land networks. Comsats help large countries
like China keep in touch with their remotest
parts. They also help countries like Indonesia,
which is a country of 13,677 islands, stay
connected much more effectively than it
would have been possible with wires and
telephone poles. Navigation satellites provide
information for navigation on Earth. They
provide signals to moving objects, helping
them identify their exact location. These
satellites are mostly used by the military and
provide information on speed, distance from
target or destination and travel time.
Orbiting the Earth
A satellite with its solar
panels extended orbits
the Earth.
Satellite signals
Dish antennae are used to
receive satellite signals.
Try these too…
The Moon (20–21),
Humans in Space
(24–25), The Industrial
Revolution (148–149),
Scientific Revolution
(150–151), Computer
Revolution (162)
Satellites for tomorrow
Since 1968, research has been conducted to develop solar power
satellites or SPS. The project has been delayed by the high costs
to build it. Once taken to a High Earth Orbit, it will beam solar
power to Earth for use in place of fossil fuels like coal and
petroleum, which are getting depleted quickly.
solar panels
193
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Science and Technology
Land Transport
The earliest travel was on land. At first, people just walked.
Then, they learnt to tame animals for travel. They rode on
horses, mules and oxen. Gradually, they made themselves more
comfortable, making carts and carriages. Modern transport on
land includes a wide range of vehicles such as bicycles, cars,
buses and trains.
Quick Q’s:
1. When was the first
wheel invented?
As early as the fifth
century BC, the
Mesopotamians
invented the wheel.
At first it was used to
make pottery but later
people realized that
wheels could be
attached to carts and
used to move things
and people easily.
2. When were the
first cars produced
in a factory?
In 1896, thirteen
Dureyas cars were
made in a factory
in Springfield,
Massachusetts (USA).
These were the very
first examples of
mass-produced cars.
3. What is the record
speed for land travel?
The latest record speed
for land travel was
achieved on 15
October 1997 by Andy
Green of Britain in a
Thrust SSC car. He
travelled at a speed of
1,233.738 kilometres
per hour (766.609
miles per hour)!
Moving in luxury
Land transport has made
much progress in the
twentieth century after
the development and mass
use of the motor car.
194
Q Why did early man need to travel?
A People have always needed to travel to
hunt or to trade with other people.
Sometimes they needed to shift home when
the rains failed. At first, they tamed animals
to carry them. Later, when the wheel was
invented, the animals were attached to
vehicles. Until recently, even human beings
were used to transport others. They carried
litters or sedan chairs in which the rich sat.
Q When did roads improve?
A As civilizations grew, people needed
more and better roads to trade and to
conquer new lands. The Romans were the
first to put time and money into making allweather roads. Rather than just smooth over
a clay surface, they dug beds and filled them
with crushed stone for a firm support.
Penny farthing
One of the early bicycle
models that has gone
out of use.
The stone chips acted as a filter for rain
water to flow through so the roads did not
flood. On busier routes, they added paving
stones to ensure that the roads were firm and
dry for their chariots to move on. These roads
were used to connect up the huge Roman
empire. Over time, even chariots and carts
were improved with springs and shock
absorbers to make the ride smoother.
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Land Transport
Modern train
Modern passenger trains can carry hundreds of
people in comfort over all sorts of terrain.
Q Where were the first railroads?
A The first railroads were built in Germany
around 1550. Horses pulled wagons along
wooden rails and brought minerals out of
mines. After the Industrial Revolution, rails
were made of iron and so were the wheels.
The development of the steam engine made
rail transport easily available to carry people
and goods over long distances.
Q When did people start to use buses?
A People travelled in stagecoaches and
omnibuses pulled by horses from the early
sixteenth century. The first horse-drawn tram
cars came in the nineteenth century. The
invention of engines that ran on steam and
on fuel such as diesel and petrol led to the
development of buses as we know them.
Q When was the motor car made?
A The first car was designed by Nicholas
Joseph Cugnot and constructed by M. Brezin
in France in 1769. It ran on steam and on
rails. The first non-rail automobile was made
by Etienne Lenoir, also of France, in 1860.
He drove the very first gas-powered car
from Paris to Joinville in 1862.
Try these too…
The Industrial
Revolution (148–149),
Scientific Revolution
(150–151), The World
Wars (158–159), The
World after World War II
(160–161), The New
Millennium – 21st
Century (163), Forces
and Motion (190–191)
A road to drive on
Roads had to keep up with the development of technology
for surface transport. McAdam designed the first highways
lined with soil and stone, which is still known as macadam.
The highways were higher than the land around, so that rain
water could drain off. Later, these highways were tarred and
the surface was called tarmacadam or tarmac. Modern roads
are built of asphalt cement or concrete.
Q When did the first cycle roll?
A In 1680, German inventor Stephan
Farffler made a hand-cranked tricycle. Later,
he gave it another wheel to improve its
balance. In 1817, Baron Karl von Drais of
Germany made the draisiennes, a wooden
bicycle with a seat and handle bars. But since
von Drais didn’t think of pedals, the rider
had to push with his feet on the ground.
The first modern bicycle was built by
Kirkpatrick Macmillan of Scotland in 1839.
195
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Science and Technology
Water Transport
The idea of travelling by water probably came to people when
they watched logs and leaves float down a river. After land, water
has been the second most popular medium of transportation
used by humans. Early humans built simple rafts, which were
improved upon in every way over thousands of years.
Quick Q’s:
1. What are modern
ships made of?
Boats and ships
continued to be made
of wood for centuries.
With the start of the
Industrial Revolution,
people began to use
steel to build ships.
Today, ships are also
made of aluminium
and fibreglass.
2. Who was the first
person to sail around
the world singlehandedly?
American seaman
Joshua Slocum was
the first man to sail
around the world
single-handedly. He
started off from
Boston on 24 April
1895, and returned
to Newport, Rhode
Island on 27 June
1898, having sailed
74,000 kilometres
(46,000 miles) in
over three years.
3. What is a hovercraft?
The hovercraft can
travel on water and
land. It stays suspended
a few centimetres
above the ground or
water surface with the
help of an air cushion
that it creates by the
thrust of its jet engines.
It is used as a fast
patrol boat by the
police and military of
several countries and
also for water sports.
196
Q What were the first boats like?
A Rafts or planks of wood were probably
the earliest modes of transportation by water.
The earliest boat found dates back to 6300 BC.
The boat was a hollowed-out tree trunk, also
called a dugout. Some people sailed coracles,
which were boats made of animal skin
stretched over a wooden frame. Oars changed
water transport. They allowed people to
decide where they wanted to go, rather than
depend on the current. Around 4000 BC, the
Egyptians made long narrow boats powered
by many oarsmen.
Q When were the first sails used?
A By 3000 , people knew how to tie a
BC
cotton sail. Sails allowed people to use wind
power instead of muscle power. Now people
used ships for trade. By 1200 BC, the
Phoenicians and Greeks built trading ships
that had special places to
store the cargo. By 500 BC,
they had ships with
two masts.
Galleon
Huge sailing ships called galleons carried people and
goods across the seas of the world during the Age of
Exploration. The Spanish galleons were the most famous.
Q How did ships navigate?
A Early ships had to sail close to shore as
the sailors could not find their way in open
sea. By about 100 BC, technology improved
and the sailors could navigate with gadgets
like the astrolabe. The early Chinese used a
spoon much like a compass. Sailors from
other countries also used a lodestone, which
is a natural compass. By the twelfth century,
the magnetic compass was in use. As the
science of cartography (mapping) improved
in the Middle Ages, getting lost was less of
a risk for sailors. In 1757, the sextant, a device
to measure latitude, was invented.
Luxury cruiser
Modern cruise ships
carry tourists in
luxury and are
very popular.
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Water Transport
Q What was special about the Viking ships?
A By the late 1000s, the fierce Vikings of
Scandinavia ruled the seas. Their famous
longboats were about 24 metres (80 feet)
long and 5 metres (17 feet) wide and were
rowed by 40–60 oarsmen. Vikings also used
small rowboats called faering for swift attacks
on their enemies. By the twelfth century, the
Vikings knew how to use a rudder to steer the
ship. This gave them more control than the
side steering oar. All the Viking ships were
slim and fast, so they could launch deadly
attacks on merchant ships and coastal areas.
A titanic disaster
The Titanic was a British luxury liner that weighed 46,000 gross
tons. It was one of the grandest ships ever built, and was
believed to be unsinkable. On its first voyage from Southampton
to New York City, it struck an iceberg about 153 kilometres
(95 miles) south of Newfoundland around midnight on 14 April
1912. It sank in less than three hours, taking about 1,513 of the
2,220 people on board with it.
Q Was inland water travel different?
A While sails came in handy on rivers,
streams and canals required special
technology to get boats on the move.
Around 984 AD, the Chinese discovered how
to make an inland canal lock. This connects
canals at different levels and needs sound
engineering skills. By 1373, Holland had
a system of canal locks. On canals and rivers,
boats were often drawn by horses against the
flow of water, and tow-paths were made on
the banks for the horses to walk on. As
engineering skills improved, sometimes
canals were made by tunnelling under a
mountain instead of going around it. Today,
many canals that were earlier used for
industry are tourist sites and nature reserves.
Q How did water travel develop?
A During the Industrial Revolution, water
travel entered a new era. The development of
the steam engine in the eighteenth century
led to the first steamboats, which had paddle
wheels to move against the current. By the
late 1800s, the first iron ships came in, driven
by the screw propeller. Vehicles for travel on
water have now become very specialized, from
the huge tankers that carry oil to luxury
yachts and small speedboats.
Q What are submarines?
A A submarine is a ship that can be
entirely submerged underwater. Submarines
became popular during World War II since
they could launch surprise attacks on enemy
vessels. Early submarines had to surface often
to replenish their oxygen supply. Today,
submarines use nuclear power or liquid
oxygen to propel their engines and can stay
underwater for several months.
Q What are ships used for today?
A Water craft can be used for virtually any
purpose now. There are car ferries and
tugboats and water sports vehicles like rowing
boats, kayaks, yachts and motorboats. Most
big ships carry cargo from one port to
another, but there are luxury ships called
cruisers which carry many tourists at a time.
Rarely above water
The sleek shape of the
submarine allows it to
move fast under water.
Try these too…
Oceans (34–35),
Discovery of New Lands
(144–145), The British
Empire (146–147),
Scientific Revolution
(150–151)
197
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Science and Technology
Air Transport
Faster than sound
The Concorde was a commercial
plane that flew faster than the
speed of sound.
Man has always wanted to fly. Early experiments with
air travel included fancy kites, gliders and even artificial
wings. Two types of aircraft can be used for air travel.
Those that are lighter than air, such as hot air balloons,
and aeroplanes and helicopters which are heavier than air.
Quick Q’s:
1. What is the
Concorde?
In the 1960s, jets that
could travel faster than
the speed of sound
were developed. These
were called supersonic
jets. The Concorde was
a commercial
supersonic jet which
could fly at a height of
17,500 metres (60,000
feet) at more than twice
the speed of sound.
2. What are airships?
Airships were among
the earliest aircraft.
They were filled with
hydrogen gas or
helium, which helped
them to float. Enginedriven airships, called
Zeppelins, were widely
used by Germany in
World War I to launch
bombing attacks on
enemy territory. Today,
flexible airships are
used in advertising.
3. What is a seaplane?
Seaplanes, developed
by Glenn H. Curtiss,
can land on and take
off from the surface of
water. They are useful
for reaching areas
where no other
transport is available.
There are two types of
seaplanes. Floatplanes
are planes with large
floats instead of wheels.
Flying boats are planes
that float on their
bellies when they land.
198
Q
Who were the first scientists to study
air travel?
A In the thirteenth century, Roger Bacon
declared that he was sure air could support
aircraft. At the beginning of the sixteenth
century, Leonardo da Vinci studied the flight
of birds and invented the propeller and the
parachute. He made designs for three
heavier-than-air craft, including a helicopter
with a rotor that helped it rise vertically, and a
glider with a wing fixed to a frame. None of
these was practical at that time. But they were
based on the science of flight.
Joseph Michel
Montgolfier
Joseph Michel and his
brother Jacques Etienne
Montgolfier invented the
hot-air balloon. While
watching wood chips rise
over a fire, they realized
that the burning created a
gas that caued any light
material over it to rise.
The same principle was
later used in airships.
Q What were the first aircraft like?
A Hot air balloons were the first ‘aircraft’.
In 1783, the Montgolfier brothers successfully
launched an unmanned hot air balloon in
France. The balloon was a large linen bag
filled with hot air. The light, hot air carried
the balloon over a distance of 2 kilometres
(1.3 miles) in a flight that lasted 10 minutes.
Later, with improved designs, hot air balloons
could reach a height of nearly 2,400 metres
(8,000 feet) and travel a long distance.
Hydrogen-gas balloons were an
improvement on the hot air balloon.
Hydrogen could lift the balloon easily without
being heated, as it is lighter than air. In 1785,
Frenchman Pilatre de Rozier tied a heliumfilled balloon and a hot air balloon together to
fly across the English Channel. Unfortunately,
Rozier died when the balloons exploded.
Q Who made the first flight in a
powered aircraft?
A The nineteenth century was important
for the development of aviation. Sir George
Cayley experimented with kites and gliders
that could carry people, and he designed a
helicopter. But it was not until the twentieth
century that the first flights were made.
Brothers Wilbur and Orville Wright designed
and constructed an aircraft. On 17 December
1903, in North Carolina in the USA, each
brother made two flights. The longest, by
Wilbur, was 260 metres (852 feet) in 59
seconds. The next year, the brothers made
105 flights. One of them lasted more than five
minutes. In September 1908, Orville Wright
flew for more than one hour. All around the
world, inventors were racing furiously to
develop the first heavier-than-air plane that
would fly successfully, but the Wright brothers
had beaten everyone to it. Shortly after the
first flight of the Wright brothers, people
across the world were starting to make
successful flights. In 1906 Traian Vuia made
a flight in Paris and Jacob Christian
Ellehammer made one in Denmark.
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Air Transport
Q Who was the first passenger in
Try these too…
an aircraft?
Earth’s Atmosphere
(26–27), The
Renaissance (142–143),
Scientific Revolution
(150–151), The World
Wars (158–159), The
World after World War II
(160–161), The New
Millennium – 21st
Century (163), Forces
and Motion (190–191),
Communication and
Satellites (192–193)
A The Wright brothers continued
their research. In 1908, Orville carried the
first passenger, Lieutenant Frank P. Lahm,
on a flight that lasted 6 minutes and
24 seconds. Shortly afterwards, Orville’s
plane crashed, killing another passenger,
Lieutenant E. Selfridge.
Q Are aircraft used only for travel?
A Air transport is used for commercial
Deadly plane
This is the famous SR-71
Blackbird of the US Air
Force. The black coating
of the aircraft is made out
of a special material that
makes it difficult to be
seen by radar. At the same
time, there is a special
fire-control radar on the
nose of the aircraft.
aviation, which includes travel and ferrying
cargo. It is also used by military forces to fight
enemy aircraft, and for dropping bombs on
enemy targets. Some aircraft are used for
dusting crops with pesticides from the air,
sowing clouds for rain and flying for sport.
Q What is a jet plane?
A Jet engines fly with the power from the
discharge of a jet from the tail of the aircraft.
They can fly at heights between 3,048 and
4,572 metres (10,000–15,000 feet). The first
jet plane was flown in 1939 in Germany. Jets
were used extensively during World War II
to drop bombs and to fight other aircraft.
Since then, jet planes have made travel by air
a reality for millions of people. They can carry
up to 600 passengers and fly at 680–900
kilometres per hour (420–580 miles per hour).
Strange bird
The helicopter was designed by Ján Bahyl in 1905. Helicopters
are propelled by rotating overhead blades. They are slower than
planes, carry fewer people and can only travel short distances.
But they are an advantage in places where there is not much
space, since they can land and take off vertically. They are widely
used for military purposes and for rescue operations, aerial
photography and fire fighting.
Aircraft carrier
Many military planes operate
out of large ships called aircraft
carriers, a practice that
developed in World War II.
199
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Page 1
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